Need to get this right, the first time.

[Mike Abberton]

If you avoid the major brands, like Dell, Gateway, etc., you will have more flexibility on which operating system they install. For example, Alienware is still selling brand-new machines with XP installed (stay away from the XP Media Center edition, though, I have heard bad things about it). Some of those specialty shops will cost a little more, but it may be worth the hassle.

Also, I would consider a 100 GB hard drive about the minimum I would accept nowadays. You might be able to bump that up a 160 GB for not too much extra cost.