You guys are so angry biased >.< (not saying i won't be either but.. its a little.. angry fanboy status)
I have 360 and a ps3.
360 = XBOX LIVE is a very worth it experience, and its what is keeping xbox 360 ahead of the curve.
PS3 = Blu Ray - yes you can ask what does 50gb do for you? Well in the future, games will be taht high, but by then a new 360 will be out. Ps3 is there for longevity investment, and it will prove itself within 5+ years, while other consoles cannot. But then again, they can ugprade and make it stronger than a ps3. Blu ray is nice.
It all comes down to what you like. Right now, 360 is still blowing ps3 out of the water, despite some good exclusives for ps3. Xbox live is better than PS Network, as its a premium online game service, while PS network is free.. what motivation is there to make it good?
Xbox live is more social. IF you dont care about that, then ps3 will be most worth it.
I have both, and i play MGS4, and etc. I always pick xbox 360 for the multi platform titles, because of xbox live. For single player, non social games, I go ps3.