Speaking as a college student entering his third year, I'll try to tell you about both sides of the coin. I used only a desktop for my freshman year and was perfectly happy. It was powerful, nice, and perfect for playing any games or editing any of my films. Sophomore year I decided to take the plunge and purchased a 12" 1.33 ghz iBook with 1gig Ram, 80Gb HD. I now carry my computer to class, am able to bring it to my friend's apartments, the library, and home every holiday brake. The iBook has not once disappointed me with its power or speed (WoW, even Final Cut Pro), and I love its tiny, light enclosure (with great wireless range and battery life I might add!). I was perfectly happy before. My desktop was extremely nice, but I dont think I can go back. While there are plenty of computers available on UF's campus, I love being able to surf the internet outside, or write a paper on the couch, or travel with WoW on my back.
What I recommend you do is to compare whatever additional benefit you think you will receive by getting a desktop over a laptop. It's clear to me that covering all of your bases (with so many varied interests in majors) is a major and valid concern. So will a desktop provide you more versatility than a laptop? Or maybe the laptop simply won't cut it (in terms of power/screenspace/durability) for the things you want to do? This you have to decide.
However, assuming you pick a laptop, then even without your budget, I wouldn't recommend a MBP. I would try to get the most bang out of the most convenient and light enclosure (without losing productivity). While it has yet to be seen, I think the MacBooks will perfectly deliver. While the MBP's are modern marvels in terms of perfomance, it is my own opinion that every inch and every pound counts, especially in the busy, frantic, walking-a-lot college environment. I have too many friends wishing now that they had just bought a small ultra-portable laptop with an additional monitor, rather then their large, heavy, hot, 2-3 hour battery eating laptops.
Whatever you decide, just make sure you get a lot of ram and HD space. It's amazing what differences those will make towards the longevity of your computer, rather than the ghz of your processor.
