I would say it would be a tie between 3 and NV,probaly NV by an inch.I havent played 2 or Tactics(does that even have a story?) by the way.

I would say FO1 ... Just talk to Harold or the Lieutenant.
* The Master is pretty good too, though short.

FO2 is tough competition though... Renesco could put me in stitches; Sulik too; and Hakunin, and Myron...

You know... I think I've changed my mind; Fallout 1 is very strong but FO2 is very close ~yet makes up for it in quantity. IMO Best is FO2.... but... then you also have to count the holo-tapes and terminal logs ~So it might be a tie.

Haven't played much so I couldn't say.

I'd say either 1 or NV. IMO 1 had better conversations and dialogue overall, but NV was better with a mind-tickling main quest/story, as in NV I always have to weigh carefully who'll I'll help, and in 1 I have no such troubles.

Oh and Tactics does have a story.

Thanks,by the way a little off-topic but should I play Tactics I have heard bad things though.

For me, its F1/2 are pretty much on par, then NV, then tactics then F3.

Edit: Tactics is a good game, its worth playing. Has a fairly interesting plot, and is quite fun. Provided you like tactical, squad based combat. You get a nice variety of different available squad members, and an array of different people/things to fight. To a certain extent there is even a degree of choices/consequences with the optional objectives. Its pretty good. What bad have you heard about it?

I have played the game (and like it), but I've not played far into it. Tactics is (my impression) really good if you liked combat in FO2 ~It's improved in Tactics... sort of. Tactics has a realtime option also, but I could not stand to use it myself; some like it though. Tactics is a linear mission game where you play a BOS initiate who does what they assign (at least for as far as I got in the game). I plan to finish it sometime.

Between Tactics and FO1... I'd recommend playing FO1 ~though be aware that FO2 corrected some interface quirks, short comings, and added things that you will miss in FO1.

I'd suggest to watch a few playthroughs of the first missions to get a impression on what's it like, for the first ones do not spoil any story content. Tactics is obviously not everyones cup of tea, so read a few articles rating it perhaps, or watch some playthroughs and if there's a demo(I don't know if there is) give it a shot. And if you like it, knock yourself out with a full version. I myself enjoyed it, playing it half way through with the real time option as I had no idea turn based was available and somehow the turn based after the real time just scrambled my play style in Tactics.

But the idea in the game is that your a member of the Midwestern BoS, a iniate at first, and after mission you progress in ranks. The story starts to roll, IMO properly only then, after..... 50% of the missions? Something in that direction. In the beginning, IIRC, the missions are about expanding the power of the BoS and later on another motive comes as well.

A fun play IMO, and you can recruit ghouls, deathclaws and super mutants into your squad along humans.