Personally I really think it depends on what type of gamer you are. A co-worker and I were having this discussion a about a week ago and come to the same conclusion.
Hardcore gamers and people who like to compete online usually gravitate toward the Xbox simply for the types of games it has and the style of the online community. From the very start, with achievements and gamerscores, you're encouraged to compete with others and try to be the very best. Also, games like Halo and Gears of War which are very very competitive, as well as very popular, are Xbox exclusive titles.
More casual gamers are more inclined to get a PS3 because of it's more laid back style. While it has it's own online community that flourishes, it's not as overt in it's display of competitiveness.
Whenever you hear of people getting together to play a console game online, or just to frag each other to oblivion, most times the console I hear being played is the Xbox. In no way am I trying to put it above the PS3. I actually own both systems. This is just the impression I get from them both.





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