I have a T400 and love it. Comparing specs, the Dell has integrated graphics and a lesser wireless adapter. Small issues.

The Lenovo is a 14", but that's my preferred size. Battery life is quite good for this class of laptop. But mostly, the quality of build and the feel of the keyboard are what separates the Thinkpad.

T400 gets my vote
 

I have an E6500 and I've used a T400 before... I much prefer the Lenovo as the build quality and keyboard is much better than the Dell.

I had very bad experiences with Toshiba reliability in the early 2000s and have not touched them since. While Dell reliability is poor as well, in Dell's case they make up for it with generally rock-bottom prices and generally pretty easy to deal with warranty service.

What's the warranty on each? Any accidental damage insurance included?

If the prices and coverage are all equal, the Thinkpad is a no brainer.

It's much lighter, solider construction (IMO) than either the Toshiba or the Dell, discrete video vs. integrated (which will make a bigger difference, again IMO, than the processor at that end of things) , better WLAN than the Dell.

Another question is "which battery does each come with" - more cells = more weight, but longer life. OTOH, if you plan to use it on battery a lot, moving to a "P" series rather than "T" series CPU will also help your battery life, regardless of model.

Oh, as for XP/Vista/Win7 - the generation of integrated graphics in that generation of machine should be fine for Aero.

HD is about the easiest thing to upgrade these days - given how often ram is getting harder to access, even easier than RAM in many cases. At this kind of midrange business machine, I'd be tempted to go SSD anyway, which is going to be even smaller.

Was issued Dells when working for corporate. Started my own business that requires tons of traveling and making loads of presentations to organizations with many different brands of projectors.

With my own money I purchased two ThinkPads: X60s and T61; the X60s is a complete road warrior and I use it daily and it gets pretty rough treatment...I'm going into my third year with it! The T61 was purchased for a non-traveling administrative asst. and she absolutely loves it.

ThinkPads have the best keyboard in the industry and its tech support IS IN THE US!!!

I disagree. OP, this is why you need to go to a store and try out the keyboards. It's so much personal preference but greatly impacts your use of the computer.

Having said that, keyboards do change within brands. My newest Toshiba has a different feel and configuration, which I don't like as well as the old ones. But I still like it better than other brands.

I've worked for many Fortune 200 companies in my career and some smaller companies. I see ThinkPads all over. I see Dells all over.

I haven't seen a Toshiba in the workplace since about 1998.

Well, he's right...go check it out though it's difficult to find a ThinkPad at retail as most of their superlative machines are ordered on-line.

As to the ThinkPad's keyboard, it's widely recognized as the benchmark for laptop keyboards and has been for more than a decade...ask anyone.

Toshiba machines were palatable in the 1990s when they were the cool alternative to Dell machines. Not so much anymore.

Thinkpad ^

I've lost count of how many Thinkpads I've owned. The last one, my T60 got dropped on my hardwood floor 3 times (you'd think I'd learn...) from heights of up to 3 feet and while there was some superficial plastic damage, the laptop kept on chugging. It didn't even shut down! I just took delivery of a new T410 about 2 weeks ago and I love it.

The keyboards are the best IMHO.

I am typing on the E6400 machine right now. Short of a small chip off the case from a ... user error ... its been a great machine. I traded in a Thinkpad Z61T for it, but mainly for the processor (the Z61 I had was a core duo, instead of the core 2 duo).

If that wasn't an issue I would still have the Thinkpad. It was a good machine. The Dell is a good machine as well as a 2nd choice.

If auh2o can make it to the Micro Center in Tustin, they usually have a T400 on display. You'll love it.

I would go for the Thinkpad solely for the DDR3 memory capability (DDR2 RAM prices will continue to rise) if you plan on installing a 64-bit OS.

It also appears that the Thinkpad's integrated graphics can handle HD video. I'd only go with the Toshiba if you plan on doing lots of graphics-intensive stuff.

I'd suggest that anyone who thinks it's likely they're going to need more than 4GB in a notebook would also be rather better served buying an i5/i7 one than a Core 2 based one. I'm not sure if Lenovo has any such Thinkpads yet; the only Dell models are either consumer-line or a very expensive "mobile workstation."

Well, you don't frequent my Fortune 200 employer...... Lots of people running Toshiba for the notebook. We also have people with Dells and the Thinkpad.

Me - I've had 3 Toshiba in a row and love them. I know others who swear by the sturdy Thinkpads. Only the Dell seems to lack any love.

My advice is the same as most - try the keyboad and the trackpad/nipple think to see which feels best.

ThinkPad T410's and T510's have i5/i7 CPUs.

One thing I'll say about the Dells: They go in and out of their docking stations faster and with fewer hiccups than ThinkPads do.