Yeah, that is one of the ways I can justify the cost of a PC over a console, if I am not an early adopter, I can get many of the games for 1/10 of the price.
Having said that, we may pick up a PS3 this Christmas. I want SSX, Marvel vs. Capcom, and some other PS3 exclusive titles.
I'd recommend against spending money on Ultimate Marvel vs. Capcom 3 unless you have people to play local multiplayer with.
Judging from past experience, playing UMvC3 online will consist of getting hit once then getting juggled in a combo that last long enough for you to go and make a sandwich, eat the sandwich, put the plate in the dishwasher, run a load in the dishwasher, and come back in time for the last hit (slight exaggeration). But if you only plan to play with others in your home (couch versus, instead of online versus) or plan to invest hours upon hours into improving, then have at it.
But I suppose the same could be said of almost any fighter with online versus.
(IMO, Tatsunoko vs. Capcom is more fun than UMvC3 for the non-hardcore fighting game fan. TvC is way more fun than I expected it to be.)
It's also been my experience that the most-hyped PlayStation exclusives are good, but it's the more obscure system exclusives that really shine (on the PS3, the PS2, and the PS1).
EDIT: Kendrik should probably weigh in on UMvC3 to balance out my opinion.
EDIT#2: You might also want to wait for the third iteration of MvC3 before spending money. It's not
certain that Capcom will release a third version of MvC3, but, given Capcom's track record, it's highly probable. I made the mistake of buying SSFIV before Arcade Edition was released and I'm still a little salty about it.