What field are you planning on going into? What are you planning to study? That could play a key role in computer choice.
That said I will never go back to a windows operating system, period. OS X (apple) has windows beat hands down in the operating system department. Full of features (that I actually use!), intuitive, customizable, user friendly, adaptable and it never crashes on me! Say good bye to "fatal error", "illegal operation", freezes, viruses, worms, etc. I may move to Linux (for reasons I'll describe below), but not back to Microsoft!
Because people will want to know: The new macs will boot windows (XP or Vista) and you have some options for doing this. You can partition your harddrive and boot it alongside OS X, you can run windows and only windows (remove OS X), you can run windows inside OS X using a program called parallels that installs windows (fully operational) into a FOLDER on your desktop (run windows without it actually being a true "operating system" on your machine). Macs will also boot Linux no problems and OS X is unix based, you can get straight into your unix platform from a program inside OS X (standard, but you have to tell it you want it to install). Finally, Microsoft does make "Office Mac" which is powerpoint, word, excel, etc for an OS X operating system. It is compatible back and forth with your friend's pc. New mac software and even the open source software can now also save as microsoft compatible files and read the microsoft office files. The compatibility issues are a thing of the past.
Aside from some internet games and an older version of this website I have no internet incompatibilities either (equisearch now runs fine for me, thanks guys ;) ).
Now the full disclosure: If you do buy a Mac, DEFINITELY buy the 3yr extended warrantee. It will likely pay for itself. A bit about me and my mac (Hugh). I bought a first run (bought it the week it was released, so first shipment out) macbook 2yrs ago. I love it, but it does have it's quirks (most of which I blame on it being a "first run" and no-one else has had my quirky problem). I had to replace my charger yesterday as it died (free with extended warrantee, no hassles, no questions asked. I walked in and 10min later walked out with a new charger). It will go back in hopefully next week as my case needs to be replaced (minor cracking), trackpad needs to be replaced (button no longer functions), and my hardware/software issues/quirks are escalating to the point I'm concerned (they will either re-install my operating system and reload ALL of my information or replace my hard drive and do the same, all free).
Most people I've talked to have used their extended warrantee for something, normally minor (charger, battery, case cracking) and it's paid for itself. I haven't heard a single one of them complain about the way Apple handled it. They are good to their Mac customers and stand behind their warrantees.
Basically, there may be some durability issues, at least with the laptops. On the other hand mine travels EVERYWHERE with me (including at least 6 cross country plane flights), I commute with it daily in a backpack, took it to class with me for a year in all weather, and generally use it to its fullest potential for 10-15hrs a day, every day. Two years later I'm asking them to replace external components from wear and do some preventative snooping around in the hardware section, not bad!
If you get a MacBook and not a MacBook Pro then plan on upgrading the RAM to two 1 GB memory. It makes a world of difference in the speed. Also the macbooks don't have the best built in speakers, macbook pros look like they might have better ones.
Bottom line: Buy a Mac!