Let me expand on this a bit...
There could easily be computer games (half life 2, I hear, is supposed to be great) that beat out halo.
Halo has been able to introduce many non-hardcore PC Gamers to the genre. People love the game, and it is definitely one of the better FPS's ever released.
There are many people, including myself, who will never know, and don't care to know, how good doom3 or hl2 are for one simple reason:
It's FREAKING REDICULOUS that every time a new FPS comes out, if you want to play it to its fullest potential, you have to throw HUNDREDS OF DOLLARS down the drain to upgrade your comptuer.
With an Xbox, you buy the system, and you know that every game released for the Xbox will run on your system, the way it's suppsoed to. After spending thousands on a computer to run the best games, you only have that guarantee for a year or so, if you're lucky.
Also, most people use their computers for 2 purposes: Internet/email and games. So it's much cheaper for someone to go out an buy the xbox and a pc that's got enough specs to do what they need than it is to go out and buy the latest and greatest pc with PC32000000000000000 ram and the newest ATI X470000000000 video card. Especially becuse the ati X47000000000001 video card will be released within a month, and most new games will probably require it.
I know i'm exaggerating a but, but this really is the scenario.
--NipsMG