You know, I built my own PC for less than that, and it runs near, if not the same as your new one. Eh, I just don't like Macs. Good luck with that though. I've never heard of a Radeon 9650...
If you're gonna go spend over 3000$ USD on a system for gaming well shame on you. Just go get your self all 3 consoles and you'll be saving a ton of cash. But I agree, if you're going to pay over 3000$ on a Power Mac you should only get it if you're starting a business, or if you're parents are filthy rich. I'm getting one of the new iBook they just upgraded and I'll be just fine with it.