My thoughts: Don't buy it for taking notes or using in the library or something unless it's something you already do.
If you have a desktop already, use it. If you need something better for gaming, don't use school as an excuse, buy it because of gaming. All you really need is word, excel, etc. and an internet browser. Depending on your major, you might have to compile things, I wouldn't buy a new computer for beginning programming or anything though unless you're still on a Pentium 2 or something.
A desktop is all you *need*. If you will be going home often or something, then a laptop will be helpful.
Most of the people I know that bought laptops really just use it as a desktop, if that. There isn't much of a need for one, not sure why everyone goes out and buys one, save the money, it's not cheap. If you take notes in class, a notepad and pen work well, they never crash, need updates, or need to be charged. They don't have a boot up time outside of pulling them out of your bag either
I generally advise against a laptop for college, get a simple desktop and call it a day, it's all you need. If computers are a hobby or something and you want more, then make that choice yourself.
If you do go for a laptop, I recommend the Dell Latitude's, my D620 is everything I need. It has a 1440x900 screen, 1GB RAM, a 7200 rpm drive, etc. and so it works as a good desktop replacement for my uses, even playing CSS well and while it struggles to do so, plays Rainbow 6: Vegas at lower resolutions.