Hella worth it.
Granted, I haven't tried it online yet. And the new version of SFII is still more or less a Super Nintendo game... but SFIII is easily one of the best 2D fighting games I've played. I think the only one I might like better is Street Fighter Alpha 3, and that's only because of the enormous number of characters and kick-ass world tour mode.
Besides, it's only $30.
Man I have been playing the crap outta this. I bought the import(wcode and region free) and played it back in November but there werent alot of players. Now with the US release I can play everyday!
Definaley one of the best LIVE titles yet.