I would definitely get a desktop for many reasons. Let me also preface this by saying I was in your exact situation not too long ago, and my desktop got me through college. It broke a few times, but I was able to fix it cheaply.
1. Stability - A desktop is more stable, easier to fix independantly or with the help of someone in the dorms, and will last long enough to get you through school. A laptop will only last 2 years before starting to have issues, especially if you play any games on it.
2. Convenience - Laptops are a concern, not only because of theft. Lugging it around may seem easy at first, but you will find yourself doing this less and less. The battery will only last 3 hours, and finding an outlet isn't always easy.
3. Convenience pt. 2 - It sounds like you will be in the dorms, so you will have a nice little closet...err...room for your desktop. Seriously, Dorm rooms always have a desk for your computer. If you are worried about hauling it home on the breaks, use the money you save on a desktop to buy a flatscreen moniter. That's the heaviest part of a desktop computer anyways.
4. Power - You may think you will be all business at college, and I admire that, but it's BS. You will be playing games. You will want that extra juice that a desktop offers. I did two things at college, I worked harder than I ever had, and I played harder than I ever had. You have time for both, just do the former first.