The title of this thread is self explanatory. here is some relevant information.

1. The desktop would be used primarily by my wife and my younger son who will be in 8th grade next year.
2. Majority of tasks performed be typical home and school work use such as surfing, e-mailing, some gaming (he does have PS2 and Xbox), writing school papers and reports plus managing music and video downloads (by my 12 yr old son).
3. bandwidth of my ISP is a bottleneck as my d/l speed is just over 1 Mbps and u/l speed is about 350 kbps.
4. I am thinking that the PC should serv etheir needs for the next 3-4 years, although my son's usage pattern and his needs, as well as evolution of technology provided in mainstream home PCs will change during the course of the next 3-4 years.
5. The most cpu intensive task that my son does is processing music and videos to transfer them to his iPod.
6. He is not into heavy gaming on PC but he will play some games.

I am not a computer expert, but I understand some basic things, maybe even superficially.
I know that in general, it's better to have more memory and slower CPU than a very fast CPU and not enough memory.
The main issue is how to balance or match CPU and memory.
I am willing to consider refurbished models.
I am unable to decide among three following types of processors
AMD Athelon II X2 processors
AMD Phenom X4 processors
and AMD Phenom II X4 processors.
I would like hard drive size between 500GB and 1TB
I would like either the amount of memory that makes the most sense for a given processor given the scope of the tasks I described. The route of getting the least memory and then upgrading yoruself does not often work as you ened up throwing away some of the memory that came with the system. For example, upgrading from 4GB (4x1GB) to 8GB (4x2GB).

I understand this covers a wide range of processors, partly because I know little about capabilities of various classes of processors and partly because I am swayed by comments I have read on lots of sites from people who may or may not know much themselves. Several people here are very well informed about these issues and I have far more confidence in their advice than what I read on the internet.
As an example of systems I have looked at are
HP Pavillion p6320 HP Pavillion p6320 : Phenom II Quad Core 2.8GHz CPU, 8GB RAM, 1TB HD
HP Pavillion s5310y AMD Athlon™ II X2 250 3.0 GHz, 4 GB DDR3, PC 8500, 640 GB HD
My range is roughly from $350 to $500 plus or minus 10%
There are so many variables, the motherboard, the FSB speed, the memory speed, the vido card, that I get lost.

Although this post is lengthy, I still might not have provided all all information you guys may need to help me.
The desktop they use currently is a Compaq SR1625NX with an Athlon 6400, 3200+ with 1GB of DDR RAM with a 160 GB HD. The DVD writer is ot working properly. It can write CD''s but does not write DVD's. I bought it in Dec. 2005. I have rarely used it myself. Given the cost of a motherboard, memory, an HD, and a DVD drive, it's probably best to buy a new PC.
I have a spare license for Microsoft office 2007 Home and Student edition and a Norton Internet Security, so I don't need to pay for these.

Thanks every one in advance.

My computer expert who has recommended Dell desktops for years now sez HP desktops give more for your money and better support to boot. I think you are going overboard with the tech stuff and the vast majority of the popular computer configurations will easily handle most known applications for $500 or less.

MisterNice

Thank you for your response. It confirms my opinions, which are anecdotal.
From what I have seen, Dell desktops cost substantially more than HP desktops with similar configuration. I have always felt that Dell systems are overpriced. It seems to me that Dell makes money by selling to Govt contractors where they claim to give 30% or more off vastly inflated prices. I have rarely used any support, as by the time I have had problems, they system is already out of warranty.
My budget ($350 to $500) is in line with what you stated.
I probably am going overboard. But I would still like to get a system that's optimised. I don't want to end up getting too powerful a CPU with not enough memory, too much processing power for the tasks, or more memory than the OS can address, or CPU/motherboard needs. In the process I hope to come out knowing a little bit more than I do now.

One answer that may work is an Apple iMac. Great build quality, excellent support, and the applecare warranty takes care of the system for 3 years.

Jimbo

Wirelessly posted (Palm TX: Mozilla/4.0 (compatible; MSIE 6.0; Windows 98; PalmSource/Palm-D050; Blazer/4.3) 16;320x448)

Is it within my price range? Imight consider it even though I am talking about PC's with AMD processors.

I have seen some refurbished Pentium Dual-Core desktops (with 640gb HD, 4GB RAM, and Windows 7 Home Premium) for under $300 on Dell Outlet. Requires a 20-25% off coupon, which pop up every once in a while.

you simply want something for him to do homework and a few personal items [i.e., video/music]. If that is correct, I would simply contact a local reputable PC refurbisher in your area and have them build you one.

That way you can specify the precise programs you want [e.g., Word or WordPerfect, whatever musical programs, whatever photo programs, etc.] and NOT have a machine packed with BLOATWARE.

Since the guy is local, you would probably also get better technical support.

I've bought a dozen computers in the last 10 years, and have generally found Dell to be good. I do think that the last couple of years they are on the pricey side.

I prefer to buy just a CPU, and not bundle it with a monitor. I have a number of large flat screen monitors, and it's a waste to get something bundled with something that you just won't use.

Costco used to have some very nice CPU only versions. In fact, the last two I got were both through Costco. Plus, you can return them within 90 days if you don't like them. I think they have some sort of extended warranty too.

If you want to do anything with online video (viewing/editing), a larger hard drive will be nice. Music can eat up a lot of space too. I don't think I'd get less than 750G, with a 7200 speed.

I do like the new Windows 7, over Vista and older versions of windows. I have 64 bit and 32 bit, premium version, but can't tell you the difference in speed or anything.

The last one I got for my business had XP installed, as well as an upgrade disc for Vista, and then I got the Win 7 disc too. 8 GB memory, 500 or 600 HD (I don't do any video on this system), and the common Microsoft programs (Word, Excel, etc). I think this ran about $500, less monitor.

You can really buy a lot of computer for a little, these days. Some of the cheaper computers that I got over 10 years ago were horrid. The first E-machines, Packard Bell and such just died way too quickly. I had a Compaq that I just hated. Really hard to add stuff to it. The Dell made it so much easier.

There may not be much difference these days. Let us know what you choose. Apple units can be nice, but they're priced so much higher that I think you'd be hard pressed to justify the difference unless you're doing editing.

$1199 to $1499 for new and sometimes the Apple store will have refurbished for $200 less. The refurbished look like new and come with a new warranty.
Jimbo

Thanks for your suggestion. It's completely out of my budget.

I too am looking for the CPU unit/tower alone. The budget I have indicated is for the tower without the LCD monitor. I haven't got a flat screen monitor, so at some point I will buy one.
I am not a COSTCO member. Their website indicates that they require a minimum order of 10 for refurbished units. New ones cost more than the refurbished ones and are less capable than the ones I have been looking at.

If converting video formats to that for iPod is video editing, my son will be doing that. I am looking at 500 GB or more. I think most of them are 5400 speed.
I do not want Vista, as I had a Vista laptop. I had a great deal of difficulty networking a mix of XP and Vista computers. It took lot of time to find a way to print from my Vista laptop to a laser printer connected to an XP desktop.

This is about the kind of system I am looking at. I have seen some refurbished ones with a quad core processor, 8GB DDR3, 1TB HD for between around $600 plus 10% minus 5% range. I already have three licenses for Microsoft Office 2007 Home/Student edition, of which I am using only one. So I don't need to pay for Word Excel etc. I also have three licenses for Norton Internet security. I myself use only Word and Excel. Microsoft Works includes Word and Excel, but I think it's a trial version only. I hate when specs don't specify whether one needs to buy any Microsoft Office components or not.

Yes you can buy a lot of computer for about $500. The question is what combination of processor, memory and HD is right. If I buy an AMD QUAD core with 4-8GB, I think it might serve him through his high school years where as a dual core system might need replacement.

I have ruled out apple already. I have not looked into any apples as they are pricey. Thanks for your detailed and useful response.

I am always hard pressed to say one PC vender is better than another. Rather, folks tend to be more comfortable with a particular brand (or have been burned by a different brand) and make recommendations based on that. Generally speaking, if you go the refurbished route, you will save a few bucks, but may not get the exact configuration you are looking for.

My advice, computer manufacturers and resellers fiercely complete on price (similar to how airlines do) so figure out the configuration you want, and see who is offering the best deal. Most every PC warranty these days is identical, and will provide the same lousy level of services, so don�t let brand name vs. generic sway you. Only thing to consider with the warranty is duration, and just like buying a car, the manufacture always wins out in the end (otherwise they won�t be offering a warranty).

An Acer Aspire revo mounted to the back of a LCD monitor might be the ticket you are looking for.

I build desktops primarily for myself but sometimes for friends and family. I have been building one pretty much every year. I have noticed that the rate of CPU advancement has slowed considerably. I am still using a 4-year old dual core processor. It is behind the technology curve now, but still enough for today's needs.

In general, encoding audio and video benefits from more cores, whereas games demands higher clock frequency.

On the CPU, I would go for Athlon II x4 or Phenom II x4 quad core and pass the Phenom (1) and dual core processors. The difference between Athlon II x4 and Phenom II x4 is the latter has additional L3 cache for a bit more.

RAM wise, 4GB is plenty for now. It's best to get 2x 2GB modules so you will have 2 empty slots for future expansion. Do get the computer with 64-bit OS like Windows 7 x64.

Hard disk should be as much as you need/afford. They are cheap now, but don't skimp on a backup strategy especially when you have a lot of data at stake.

Since the intended user is doing light gaming, the on board graphics should be able to handle it for now. Since you are looking at AMD processors, the preeminent chipset will be 780G, 785G or 890GX.

Should the gaming demand more graphics power in the future, it is not hard to install a midrange GPU (ATI HD5600 or Nvidia GTX260) for $100~$200 that gives you many times of the power of the onboard graphics. The low end don't have enough power to make a difference, whereas high end suffers from diminishing returns.

Good points. All the refurbished units I have seen, all of them have been HP, have a 90 day warranty instead of 1 yr warranty for a the new HP system is 1 year. I figured that a major manufacturing defect will show up quickly. I encountered a defect in my Compaq laptop in about six months, which, I admit is longer than the 90 day warranty. Some 1 year warranties are also difficult to use, as you have to ship the system off to the manufacturer. When PCs cost in the neighbourhood of $3000 vendors could allcate substantial sums towards tech and warranty support. Now that PCs cos a few hundred dollars, you just can't expect the same level of tech support or warranty.
I haven't used any tech support in the last 10 years. When I did call them, they were not able to help much. It took me time, but I was eventually able resolve every issue myself.
Your advice about deciding on a configuration is a sound advice and goes to heart of my requirement. Getting advice on the optimum configuration was the reason I started this thread. I posted links to specific systems to give an idea about what kind of configurations I have been thinking about.
For a given configuration, I can save $200-$300 on refurbished unit. I can use some of the savings to extend the warranty by a year to cover any risk of 90 day warranty on a refurbished system, as I don't know how much the system was abused or not by prior owner(s) and how much refurbishing the vendor actually did.
I am not averse to buying less known names. It just happens that most of the ones whose configuration was close to what I was looking for, happened to be HP. Other than Apple, which is not a PC, and Dell, which are definitely priced higher, I have not ruled out any vendor(s).