Jesus man, you really hate Microsoft don't you?
You know, Nintendo essentially had a "monopoly" in the video game market in the days of NES and the early SNES. The market is so saturated with crappy systems and even crappier games now that Microsoft can hardly be accused of doing anything that hasn't been done by every last one of its competitors in this arena. Sony got PLENTY of exclusives that could have just as easily ran on any other platform. Nintendo always has.

But when Microsoft does it, it makes baby Jesus cry? Okay, so using that logic, if every game was available on every system so that no one had any real advantage over the other, which one would you buy? Exclusive titles are what keeps the consoles competitive. Kudos to Microsoft for realizing this and roping in some actual good titles instead of banking on another Halo debacle.

Besides, more than likely, GTA4 will be about as 'exclusive' as it was on PS2; it'll show up on the XboxO for about 6 months, then trickle out to the PS3, and eventually the PC. Rockstar isn't that stupid.