Compatibility issues with PC's and Apples are a myth.
I have used an iBook the entire time I have been in my program. The battery outlasts the other PC's in class, by one to two hours. I have better wireless compatibility. I have more options in a smaller package. I have a smaller form factor for more features.
I have run my laptop for 23 days straight without it crashing(I.e. I did not turn it off, or reboot it in that time). When I close the lid, it goes immediately to sleep, and when I open it, it wakes up immediately. I can burn disks of the power points while in class, and distribute them to whoever wants them, after recording the lectures on the built in mic. Don't type while doing this though, but i do have an external mic.
With Office X, I have had less compatibillity issues, than the rest of the class, and they are on PC's. I carry my computer with me everywhere, and use it all the time. My friend with a Dell, won't carry his, because it is too heavy, plus his battery won't even last through a two hour lecture.
Another thing to think about, Mac's typically hold half of their value, at two years. Lets see a PC do that.
I am very biased, and love my Mac. I can say however that it is better than any PC I have ever owned, and I just got rid of three PC's less than a year ago.
People in my class, are so impressed with the apple computers, my friend and i use everyday, that three of them have switched, and two more are considering it.
If you are worried about the complexity of learning an new OS, don't be. OS X is easier to learn than any of the M$ crap out there.
If you have more questions, post them here, and I will try and answer them.