Buy in mid-2008.
Most of the games have been delayed and there are very few PS3
exclusives right now.
PS3 games have generally been disappointing and have not lived up
to expectations.
MGS4 and GTA4, Killzone 2 and Playstation Home are all coming out
in 2008. Let those games come out first then make a decision.
But if you are dead set on getting a unit now, Uncharted: Drake's
Fortune seems to have promise. It's a male version of Tomb Raider.
Ratchet and Clank appears to be pretty good as well.
The 360 just seems to have a lot more promise right now though -
and the games are cheaper. $70-$80 per game vs $100 for PS3
games.