bootcamp......... then windows vista/xp. all sorted
I use a MAC G5 at work, but have vista on it aswell. I don't really OSX that much, but it all looks very nice. as for apps....... i only have the usual stuff on there, photoshop/flash/dreamweaver etc.
If you are into video editing, final cut studio is pretty trick!
There are some interesting 3rd party apps, most of which are free on apple's website. The whole spinning cube/virtual desktop thing was very cool, but latest OSX has its own version built in (sadly no spinning cube though)
at the end of the day, pretty much anything you can get on a mac, you can get on a PC, except for those smaller 3rd party apps perhaps.