Hmm... I thought I would add something to this thread as it has popped back up again.
As a MacBook Pro user, I have a decent graphics card inside: the 256MB Nvidia 8600M GT. Now, games are lacking on the Mac front, but I did pick up some Intel-only game a year ago. I never play the game mainly because it was a strategy game; it grew too boring and repetitive after awhile. Plus, the game really got the fans going. But, the graphics were superb on high settings. Not the greatest graphics mind you, but certain aspects and objects of the game turned out very well with higher settings enabled. Sometimes, the game looked like a movie, which is interesting indeed.
I don't particularly like that game I have because the gameplay for it isn't great overall, but my point is, Macs are built with quality hardware inside. The Macs with real graphics cards can play games very well. The only problem is that there are few games scripted specifically for OS X, hence some Mac "gamers" turn to Boot Camp. The lack of games is due to Apple's lack of a focus on that market and the developers lack of interest in writing for OS X. From what I heard, certain portions of OS X are harder to work with over DirectX, hence developers turn to Windows. If both groups banded together to bring games to the Mac, I'm sure it would be a great success as Apple's other branches have been.
Personally, I think that Apple has something to gain by entering into the gaming industry with a gaming-oriented device. Apple has conquered the digital music industry, and they are most certainly dominating (or are going to be) the mobile phone industry with the iPhone. The Mac is gaining more users on a massive scale. Gaming is the only thing left in a sense. iPhone 2.0 software is going to support several games, at least from what we saw at WWDC, so that ay be a start for Apple. The iPhone is the platform to be working with now, after all. What Apple could do is revamp the Apple TV yet again to support gaming and further iTunes support with it, but that would not work in the long run. I bet that it would make the Apple TV seem like an overcooked product, so to speak. Not good. Or, Apple could release a customizable Mac desktop akin to the Mac Pro, but cheaper and aimed for gaming. But that could steal sales from the iMac line, and releasing a similar notebook would steal from the MacBook Pro. Apple would have to be very careful about this. Introducing a completely new product like a gaming console would probably be a safer bet for them, but who knows what would happen. Nevertheless, Apple has proven that they can take and concept and "perfect" it. They have done it three times already.