It largely depends on what you want to do with your notebook. If you're just looking at web access, writing papers, or other entertainment type things, the iBook would be great for you (hell, even I want one).
However, some programs you might need for some majors are PC specific. No way around it.
As for your reasons for wanting an Apple:
1) Apples don't last any longer than other quality laptops.
2) Apple laptops can get far less battery life than say an IBM laptop. But their battery life is very respectable compaired to most PC laptops.
3) Apples have no viruses because no one writes viruses for them. There are still holes in OS X, just no one chooses to exploit them.
4) You can't play games on many laptops unless you want to play Starcraft, Diablo II, etc.
I still wish I had an iBook though
[EDIT: After reading Las's post]
I agree almost entirely with Las, but there are a few things we disagree on:
Laptop battery life is based largely on usage. I can stretch a high-capacity battery on my IBM to 8 hours if I had to. I can stretch a normal battery to 5+.
If you know how to purchase a laptop you can get a very, VERY, nice iBook for under $1,300. That's an extra $300 - $400 for portability and comfort. Especially in a college dorm room in the lack of space you will appreciate a computer that takes up less room than your pillow.