I really wish the developers hadn't scrapped the single-player campaign of Warhawk for PS3. I still enjoyed playing the game online though.
Uncharted: Drake's Fortune (Project Big), MGS4, Eight Days, The Getaway 3, Resistance: Fall of Man, Final Fantasy XIII, some great reveals at the time even if a couple of the titles were unfortunately cancelled. The $600 price reveal of the PS3 was insane.
In hindsight, I should have definitely bought GTA IV for the Xbox 360 instead of PS3 but I was a big PlayStation fan at the time.