Just kidding, It would all depend if I could repawn. If I could, probably Assassin's Creed, MW3/BF3, or Batman. The main reason for this is because those are the games I am currently invested in. =P
Sounds a lot like real life, huh If I could make my environment simulate a video game, though, I'd probably have to choose Left 4 Dead. Sure there's zombies swarming infinitely around me and I'd probably **** my pants trying to not get eaten alive (not to mention the problems arising due to lack of food, shelter, rest, etc.), but it's a video game, so you don't feel pain or die (physically, your avatar may, but the player doesn't).