Just curious: Who ever said you have to use Vista or even 7? XP still works great for me even on newer computers, and until Windows 7 can start using less memory and stop freezing up on me, I'm sticking to XP.
One thing these guys kinda failed to ask, what applications are you most likely going to be running?
(This is why getting a laptop from the college for free is just so much cooler sometimes
)