Single Player: Uncharted all the way
Multiplayer: Gears of War, although Uncharted MP is still young and will probably improve.
I voted Uncharted 3 because I like just the entire idea of the game and Uncharted has far more possiblilties storywise, with Gears of War, although I love it, the story can't really go anywhere after 3 and the only saving grace for the series after 3 will be the MP. I mean lets face it how many times can you fight off an alien invasion without it getting stale. As opposed to how many action-packed adventures you can go on with Drake. In the end it comes down to one word, potential. And the Uncharted franchise has just that. I won't go into details about graphics but I will say this. I expect Uncharted 3 to set the standard for console graphics just as Uncharted 2 did.