There are a lot of web sites comparing the graphics between the two systems. Looks like the 360 has much cleaner lines and sharpness. There are a lot less jaggies (at least from the few sites I could see). Looks like I will stick with the 360 version.
I'm really not sure how those shots were taken, but I did an extensive nitpick last night, going back and forth between versions. Both hooked up via HMDI on a Samsung 50" DLP, and it looks like the 360 has a little
more antialiasing, and the sharpness looks the same to me. I think in some of those comparisons the PS3 images were direct caps, but via component, which might make a difference. I dunno.
As I like to obsess over stuff like this, the difference really isn't as big as it's made out to be. Much less difference than, say, Madden football on the old Xbox vs PS2. Even more so once you buy the game for one system and start playing it without going back and forth. I'd say the difference is graphics is about as equal in weight as your choice of controller, or the difference in load times (360) vs. no load times(but w/ HD install).
Make your decision on whatever of those is most important to you. Both look fantastic in the heat of battle, and it's a no-lose either way. I'm just glad they're just so darn close that we can obsess this much over it and it's still almost a wash as to which is superior.
Either way, Capcom should be commended. Whatever system, buy it!