Very different games.
I recently (read: Finally) got around to playing F2, I really enjoyed it, I still prefer fallout 3 though, however I can see why people prefer 2.
They are far and away different styles of games, saying fallout 2 is better than fallout 3 or the other way around is like saying Mario Galaxy is better than Left4Dead, you may prefer one but that doesn't make the other any less good.
As a side note I hate Mario Galaxy and want to beat it to death with sticks.
Also can we drop this act? It's getting tired, the fallout games have changes, deal with it. No ones view is any less important than anyone else purely because they played such and such "back in the day", if someone thinks a game is good is comparison to another game they and many others thought was good, then that game is good, in the same way that if you think it's bad in comparison to another game, but still enjoy it, it's still a good game, you just prefer the other game.
This constant "F1/2 was better" in every bloody thread mentioning F3 is getting really, really dull. So you prefer F1/2, congratulations, you can form your own opinions, stop bleating about it like it's all that matters.