I think it depends on the type of game. It seems to make sense for something like Bioshock (new IP, the console it's released on 1st is known for that type of game). What I don't understand is all these JRPG developers agreeing to such deals with Microsoft. That doesn't make sense to me, this genre is worlds apart from Halo etc which is the sort of game a substantial amount of 360 owners bought their console for.

The people complaining should be grateful that most of the exclusives Microsoft is securing are timed. There's at least a good chance of the games coming to other consoles. The same can't be said for Sega fans that had to watch Sony screw them over (I remember Sony securing exclusive rights to Tomb Raider 2 for example) even though the Saturn was already having a very rough time with third party support and was absolutely no threat to Sony.

This.