Dragon Age: Origins. I just...had to. I would've played it on Normal if the friendly AI wouldn't be so thick. Yes guys, those jets of flame in your face do indeed come from that pressure plate your standing on. Yes get away from them. No don't walk over them again dammit!! Death ensues.
Other than that, I might put an RTS on Easy. I played Need for Speed: Shift on Easy for quite a while too. I love racing games, I love the adrenaline they give, especially Shift is epic. But no other genre can raise my blood pressure that much if it goes wrong.
Other than that, Normal or even Hard all the way. I barely play any FPS singleplayer campaign below Hard nowadays.