Do you have a link? Is it the 32-bit or 64-bit Windows 7? What is the cpu? You'll want a dual core and if it is 64-bit I say get 4 gigs of memory if you can.
My daughter has a 3 year old Compaq with 32-bit Vista, 2 gigs of RAM and a dual core cpu at 1.6 MHz and she has no problems at all watching DVDs, surfing the 'net and online research, AIM, as well as school work involving papers, power point, etc.
If she can do that on her 3 year old, not state of the art system, and you aren't gaming and all you want to do is watch movies, surf the net, and do homework, papers, etc. you are more than fine.
My vote is with HP.