For me, I need a computer that does it all. I'm an animator, techie, geek, and play as hard as I work. So to have to switch from machine to machine to suit my lifestyle was just plain annoying. But now, with the better graphics cards, and tech offered in Macs now, every things just great. Hell, heres a vid of me playing Elder Scrolls V: Skyrim on my iMac 3.4 Quad i7 Beast
http://www.youtube.com/embed/7a3EC9M45rE