I'd just like to comment that while the popular games from Windows *DO* get ported over, the ports are not the same quality as the original - the games nearly always run poorer than they do on Windows. That, and a lot of the features / updates do not work.
I am running a Mac Mini G4 - and am in the process of pricing out either an iMac 20"/24" or a Mac Pro for the simple reason that I can run my games in windows. I haven't played around with the virtualization software, but I'd imagine it'll run just fine with playing games.
I remember the old days of Commodore 64, Macintosh, and IBM. You'd walk into a computer store and see three different shelves - one for each system - and you'd see all the games. While it'd be nice - the truth is - it is not economically feasible. The Windows API is drastically different than the Mac or Linux APIs. While it is true that much of the game content (sounds, video, graphics, game logic (physics, etc) are going to be highly portable - anything having to do with the graphic hardware, operating system, or interface is going to be vastly different. OpenGL was a great attempt at standardizing much of this, but that was sunk when Microsoft did DirectX.
As far as games on the Mac - World of Warcraft is the only one that I can see worth purchasing specifically for the Mac - because Blizzard does their own code maintenance, and it seriously shows.
As far as consoles are concerned - I have my Wii (broke my Warcrack addiction) and love it, but I like realtime strategy type games as well with the mouse and keyboard - and I'm not going to find those on console systems, with the same playability as I'll find on a computer.