I have a iMac 24" and most of the computers in my house are hackntoshed.
iMac 24" October 2008
2.66GHz Intel
4Gb Ram
640GB HD
Superdrive
Nvidia 9400m
OS X 10.6.2
Windows 7 RC1 32bit
I got two Dell Mini 9's in the house, that have Snow Leopard on them, a Dell laptop (was running XP, then Mac OS X Server 10.5, now no OS) and two Dell towers (both running Ubuntu Server, one got converted to Mac OS X Server 10.6, not sure what to use on it now)
Personally, Macs for School, Audio/Video and Pictures, Windows for gaming, and linux for hacking and cracking, is how I roll