In spite of the damn near game breaking glitches and bugs I experienced during my F:NV run, I would have to say New Vegas, as it felt more in-line with the original Fallout 1/2 vibe (which I might add was incredibly formative to me as a child. Hell, I also liked Fallout Tactics for what its worth.). It also helps that Chris Avellone helped write New Vegas as well.
Fallout 3 was still amazing though. I still have my replica PipBoy from the collector’s edition pre-order .
This is the correct answer. This is the only answer.