Side by side real world performance of the PS3 and 360 would be very very similar in performance. Like it was said earlier just look at what games and aspects u want and then go with that one. The Xbox 360 is my choice, but I have enjoyed my friends PS3 as well. Im not so much a Wii fan (just dont enjoy all of the motion sensorness, though older games on it are cool with the downloading and readiness of them.) Just remember that they dont make the games and then just send them out without testing frame rates with consoles. They have specific hardware and they test the graphical quality and frame rates before sending them out, so you can almost think of them as having fix framerates, but as we can see they do drop in frames ever so often. That is a vague way to look at it, but it should give u an idea it to why they cant benchmark them.
Though if I had to comment from a technical aspect, I like the Xbox 360 the most as far as GPU, Mem, and "CPU"! I like the architecture of the ati card in the xbox more than that of the nvidia one in the ps3, especially with 10mb of onboard cache...dont know why i just love it. lol, well the CPU's, offset each other alot from what i have heard from developers, and basically they are both ****, but thats alright...they will find a good way to use both of them. The memory usage is a bit better in the 360, but once again so very similar that even from PC standards it would make little difference. The only difference between the 2, is blueray and about 100 - 200 bucks! lol...just my 2 cents!
The actual reason for me getting the 360 is more because I like Forza, Halo Series, Sports games are the same, will play halo wars, and a few others. But i may get a Ps3 soon because i have enjoyed it at my friends and i want to play killzone 2. Still PC all the way though...lol
P.S. Ignore the people who will flame you for a console thread...the question was alittle repetitive, but still you did have a question you wanted answered and overall that is what forums are for, is it not?
Best,
3Ball