Heavy Rain. It's one of the most engrossing and emotionally gripping games you'll ever play but most people don't even try it cause it's "all quicktime events" and "not really a game"
Also Resistance 3 but that's mainly because I believe it deserves to be up there with HL2 and Halo 2 as the best FPS games. Its single player is just incredible. The upgrading weapons and the creativity put into them and the enemies just pushes it over the top for me.