Depending on what was your trouble with the first Uncharted, I'd say pick Uncharted 2. It has a lot more variety, and overall it's a much more polished game. It's not radically different though, so if it's the basic idea you don't like, you might not like Uncharted 2 either.
'Fun' fact related to Uncharted: I finished my first playthough of Uncharted 3 just last night. I loved the first two, but only recently got Uncharted 3 because I hated the online pass thing when the game was released (and still do, but at least the game was cheap now).







