Out of curiosity, which college are you going to and what are you majoring in? Some schools have requirements or recommendations as to what computer they want you to have. Some Majors will have certain requirements as well.
Just as a general guideline, I typically prefer Asus and Toshiba when it comes to PCs. Windows 7 is a given on anything you buy these days. I'd recommend a unit that has at least 3 or 4GB RAM, 320GB Hard drive, and the screen size depends on what your preference is. Most models hover in the 14.1-15.6" range for college students, since they tend to take them around more often.
Best Buy has a pretty good back-to-school bundle deal on their website right now where you get a Toshiba laptop, 26" TV, Microsoft Office, XBOX 360, Camera, Backpack, Camera case, 3 Month XBOX Live Gold subscription, $20 CinemaNow card, $15 Napster card, 1 year of Antivirus, and it includes the computer being setup for you for $1299.99. It's a great deal if you need all the stuff in the bundle. There are other smaller bundles through them too.
http://www.bestbuy.com/site/Compute...er/pcmcat202700050008.c?id=pcmcat202700050008