2, easily.
1 felt too rough around the edges, 3 felt too clinical.
2 hit the sweet spot. Excellent game.

 I didn't know you've ever even played an Uncharted. lol

Only played 2 and 3. And so 3 wins, due to coop mp fun with friends. 2 had better and longer SP and I also really liked the MP. But I could not play it coop :(.

I only played a little snippet of the first part of 3... it was really neat, but not neat enough to draw me away from other games for too long at the time.

219 votes for U2
215 votes for U3.

Wow, very close poll results.

Personally I feel U2 was better. It is more of a case of timing though. U2 rocked the industry when it landed, by being so far beyond everyone else in terms of pacing, narrative and visuals. The game was just astoundingly well made and after the respectable, but not incredible first game, it caught everyone by surprise. U3 was a brilliant game, but only managed to emulate the 2nd and while it did offer a new experience, didn't quite reach new heights.

This is how I'd describe my thoughts too. 

2 was my first intro to the series, and I was blown away. 3 was also great, but I didn't like the story as much. I also enjoyed 2's MP more, although I cant put my finger on why exactly.

DF is my fav single player wise it was more challenging b/c it had more enemies in each area you couldnt just play recklessly like in 2 and 3

as for MP it goes to UC2 hands down ive put over 30 days play time in that even though im currently playing UC3 MP to this day i liked UC2s Mp b/c at the time it was a new fresh MP experience for me the maps are simple and it was overall more balanced than UC3

2 was a big step up from 1 and it was a surprise as to how good it was.
But imo uncharted 3 was still the better game overall. It even included co-op levels from uncharted 2.

Liked Uncharted 2 the most

uncharted 3 is the best.