Far Cry 3 for Story Far Cry 3 for gameplay Far Cry 3 for lasting appeal :)
Assassins Creed is another option, but truthfully I felt like the game had a lot of meaningless filler in it that was meant to lengthen the game, but didn't fit organically in to the world (not unlike plenty of other open world games), Far Cry 3 is like a big destructive play-box. Plus you can light bears on fire and send them to murder people.
84% of people make up their statistics. If you are one of the 16% that don't, put this in your signature.
Far Cry 3 is easiest the best over there, all around. Yes, it's another FPS, but it's an FPS done right. The only one on par this year is Borderlands 2.
Hitman is fun as hell, though. Some mechanics might not appeal to everyone, but it's a solid title, and very open to newcomers of the series. Old time fans might not enjoy the lack of the previous' titles open ended(ness)
Assassin's Creed 3, as far I as I know, was a major disappointment to everyone. Myself, I gave up on buying it, which is a shame. It looked like the game had some new trinkets to spice up the gameplay(hook dart, bow and arrow, musket-wielding enemies...), but I hear the gameplay is plagued by the same problems, Connor is as uninteresting a character as they come and Desmond's story is forced down on you(like it has been in the previous 3 games. Does anyone even CARE for Desmond anymore?)
Far Cry 3 should be the safest bet here. But take a look at Hitman beforehand.
-FREEZE! -I'm a robot, not your refrigerator.Marvin