Cough OS OS OS cough cough.
In the OS world, LINUX is best, OSX is next, and then there's winblows. (is there a viable 64 bit version of windblows YET?)
So the MAC gets you the secound best OS on the planet, that STILL lets you play more games than Linux.
GENERIC Intel setups = poor OS, no style, ugly, un cool. This is where most of the world is, uncool.
CUSTOM Intel setups, can have cool OS + gaming OS, wicked cool moded cases, and cheap. Cool and cheap, that's great.
MAC = cool OS, some games, not cheap, but way cooler than generic Intel.
Here's a test. Bring 10 dates home over the course of 10 months. (you can get 10 dates a year, right?). Have your current system set up, (go ahead and get that Dell LCD, it still doesn't look as cool) and show it to 5 of those dates. NOW, go buy the G5 with the top Apple monitor, and show that to the other 5 dates.
I bet you get a more impressed date, and higher % chance of getting lucky, with the apple system.
And yes, people DO care about the prestige / coolness factor of their system, go listen to the case modder forums for a little while.
See, there's a niche for everything, even a MAC.
<tounge firmly planted in cheek>