i'm torn between 2008 and 2009 but i'd say 2009 because it felt like the year the PS3 found its proper footing and started releasing consistently great games alongside the slim revision and better marketing w things like the kevin butler ad campaign. it already had some the previous year like LittleBigPlanet, Resistance 2, Playstation Home, etc but this felt like where they really went on a roll and didn't stop with them and had a clear vision of what they wanted to be.
Uncharted 2: Among Thieves
Ratchet & Clank Future: A Crack in Time
3D Dot Game Heroes
tons of variety and all those games ended up being great. good times.