Assuming you are looking at a Windows-based system...

1 If you are connecting to a Digital Video Recorder a FireWire port is very useful - if not USB 2.0 (get at least 2, 4 if possible) is fine as almost all accessories will connect via USB.

2 It's helpful, but not necessary. You can puchase a reader that connects via USB for $20.

3 2 at least, 4 if possible.

4 If video memory is shared with main memory it uses some of the total memory for video, so it's not as good as dedicated video memory. With 512 meg of memory, and assuming you'll be doing genral purpose work - email, word processing, etc. it should not make a significant difference. If you are going to do any type of digital photo or video editing, or heavy game playing avoid it.

5 A 10/100 card will be fine. You do not need a 1 gig port in 99% of places.

In my experience the IBM Thinkpad "T" series is the best, but it's probably out of your price range, unless you find a very good sale. I have had good luck with the Dell Inspiron laptops as well - you can find discounts on sites (such as www.techbargains.com) where you can configure a Dell portable at $1,500 or more, and take $750 off with the discount code, so finding a decent system for $1K is doable. I like the 600m for example.

Bruce