This is a tough one! 2009 and 2010 were both spectacular years....
In 2009.. We had Uncharted 2, Demon's Souls, Infamous, Killzone 2, Batman Arkam Asylum, Bayonetta.
In 2010.. God of War 3, Red Dead Redemption, Bioshock 2, Heavy Rain, Grand Turismo 5, Assassin's Creed Brotherhood, Vanquish, Battlefield Bad Company 2.
I think in terms of output 2010 probably edges it out. Which is the same year as my favourite year for games for the 360, funnily enough