I wasn't all that blown away by 3, I preferred the first two. Yes, even the combat, if you can wrap your head around that. It's not easy to decide between 1 and 2 though.
Like Gethsemani said, Fallout 1 just felt better somehow. But even with patches, it's terribly unpolished. On my first playthrough, I never even found the water chip: I got my time extended by 100 days by the water merchants, and played the whole game through in that 250 day time limit. And that's just one example of strange stuff that could happen to you.
Fallout 2 also had its share of problems, but not as many and they were less extreme. Overall, it was just a far more tight gaming experience. It was also even darker than the first one, which I enjoyed, but otherwise, the atmosphere wasn't as great as in the first one.
In the end, I gotta go with Fallout 1, since they were always about the idea of the wasteland for me, and I have a thing for originals.