For the price of one of the new M$$$ Xbox 360's I could upgrade my computer to be (roughly) on par with it in terms of graphics. Heck, quite a few of the games available for the 360 are available on the pc as well (Quake 4, Call of Duty 2). I, for one, am not particularly impressed by what I have seen from the 360. So far as I can tell, my 2 nvidia 6600's in SLI mode prove graphics on par with what I've seen from the xbox 360, and they cost (together) a little over $300.
Now, that may be the same price as an xbox, but considering the other functionality I get out of my computer, I have a very hard time justifying the purchase of a 360. I think it makes more sense to upgrade your computer than it does to purchase a console, which cannot be upgraded (relatively speaking) and will be obsolete technology within a year or two anyway.

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