@shinso ... the majority of people will NEVER buy or use anything else other than what would come on an arcade system ($200) as opposed to the PS3 ($400).
The multi-platform games that come on both platforms may be similar, but only recently has the PS3 quality been on par with the 360 on multi-platform games because of the simple fact that the 360 is almost always the lead platform. PS3 versions in the past have been plagued by performance issues as well as just plain lazy development by studios who have not yet figured out how to utilize the PS3's power.
There are no major fighting franchises (Street Fighter, Virtua Fighter, Tekken, MK, Soul Calibur) that are not out for the 360 or are not coming out. One could argue that the 360 has a better fighter library because of Xbox Live arcade that allows people to play many of their classics. I guess if you feel more comfortable with the PS3 controller for fighting games, that could sway you to the PS3. Then again, if you are buying a console to play a certain genre, you should be buying an arcade stick anyway.
@softtouch ... The 360 has more downloadable HD video on Live Marketplace, can be used as a Windows Media Extender, can be used to stream pretty much any content that is transcoded, has Netflix streaming. So aside from Blu-Ray, the 360 is far more flexible than the PS3. Up-scaled DVDs are practically of the same quality for most people anyway.
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With that said, like I have said many times before ... I do own all three major consoles and I firmly believe that I were to own just one, it would be the 360 because in the end, I buy a console to game and aside from the PS3 exclusives, the console itself offers little incentive to dust off and play.