get a PS3, it will be around longer if you ask me. and 360's exclusive titles have already been released (well, a lot of them) and PS3 has got it's main exclusives this year. its going to be an exciting year for PS3 owners.
i however own both consoles so im really not going to miss out on anything and to be honest, if i didtn have a 360 i wouldnt miss halo 3 that much after playing call of duty 4, wich you can of course get for PS3.
some games coming out are FF13 (dont know anythign about this one, not a FF fan at ALL) Killzone 2, and LittleBigPlanet, of course many others like HAZE wich i cant wait for and i think UT3 came out on the 9th of this month. those are the major ones i can thikn of right now.
from your original post, i would deffinately reccomend a PS3 for you. if games are all you care about, then maybe a 360, but in a year from now there wont be that much difference between the two.