Now that Macs are Intel-based, you can run Windows virtually very easily alongside Mac OS X and avoid all of the enterprise issues only PCs can handle currently.
The Signal School at Fort Gordon just bought a bunch of iMacs with a Windows OS (I don’t know if it’s virtual or just a dual-boot—I assume the former).
Macs are pretty cool, but I wouldn’t have the first clue how to do even a quarter of the things on them that I can do on a PC. Now that I’ve been schooled in Active Directory, Exchange, Sharepoint, SQL, Visual Basic, etc., it would make it that much harder to change over.