I am a fourth year going on five and have some advice for you.
1st. You need a good desktop in the dorms. I had a T3 and the gaming was awesome. For the price of verry little on the laptop you can setup / upgrade a desktop to do your fragness goodness.
2nd. My largest regret was not getting a laptop in college. It makes a huge difference. Having one in class (if you sit in the front) will get you serious brownie points with your teacher and they will take you much more seriously when you go to talk. It is great to take to library when doing recearch and also when you need to move your workspace due to room / appartment mates.
My sugestion w/ a laptop ASSUMING YOU GET A DESKTOP FOR GAMING.
speed -- last consideration take ur time and save $$$
Ram -- 512 will last ya a while!
OS -- apple or XP. depending on ur major linux/unix will be a necessity. My CS dept is almost 100% linux. The apple would help with that IMHO.
Networking -- most important, get 802.11b. It can be a huge help and cool factor when you whip it out and dont need any wires. Also will help when you move off campus and want to get files at fast speeds. Corse get 10/100. Also a modem is important if you ever fax ur papers for error checking.
Size -- make sure it can fit on ur desk
Drives -- get a CD-R for moving files, get a DVD for watching movies in dorms / friends TV's (great for girls houses

Keybord -- kinda important for note taking. Make sure it is comfortable.
vid card -- save ur $$$