Buy a new Windows 7 Machine get a (not so) Free Xbox 360
The Xbox 360 4GB is totally free once you realize that you have to spend over $699 on a windows 7 PC and be a student. Just think, that $4,000 grand a year tuition is REALLY starting to pay off! The specifics come from the Windows Team Blog
Get a free Xbox 360 4GB console with the purchase of a Windows 7 PC $699 or more, at participating retailers in the US from 5/23-9/3 or while supplies last. Verification of student status required. See participating retailers for full details.
You can use the PC scout to figure out what you want, but I wouldn't expect a top of the line gaming rig (or even a mid level one for that matter). If you are looking to get a gaming machine on a budget, I'd recommend Newegg.com and going the do it yourself route; it's really easy!.
If you are a poor college student and looking for some Microsoft hookups, I would totally recommend Dreamspark and hitting up your college's tech department. More often than not, the tech department will have free copies of windows products that they will install for you.