Shadow of the Colossus
That game is unreal. Probably the best game ever made, both in terms of technical achievement, gameplay breakthroughs, and overall gameplay.
Also in terms of gameplay development Prince of Persia 2008 is an amazing work. Truly it is the epitome of this generation's gameplay. In terms of design decision making, it is incredible.
Uh what else... Uncharted is great too.