Though it's arguably less enticing. MGS2 really bores the shit out of me, to be honest. It isn't that it's bad, I think the pace is just off. I've tried to beat it twice and I just get really tired of it about halfway through, though I still want to see everything that goes on. MGS3 looks amazingly awesome, but I keep trying to finish 2 before I try it! Though the gameplay looks great. That's one I feel annoyed with myself that I haven't yet experienced. I just need to finish up 2, which seems like maybe it'll happen someday. Like I went through most of AC!D not long ago, and I find that much, much more engaging on a gameplay level.
Anyway... I again point to the fact that MGS4 looks to be made available on the 360 as well. Despite K-Man's insistence that the port will probably suck (and that's certainly a possibility), I don't know that it's going to be what pushes PS3 where it really needs to go. The fact that it isn't PS3 exclusive is going to hurt the PS3 whether the 360 port sucks or not.