Fallout 3 GOTY edition would be my suggestion. While it is true that the story is clearly not up to par with the original two Fallout 2-D pixel titles, and there is a severe lack of darker-than black humour, it's still pretty much a good game, an enjoyable ride and it has its moments of some much-welcome freedom and WTF-is-happening silliness. The add-ons, which will be all contained in the GOTY edition, are also fun expansions to be played at your own discretion.
I also enjoyed playing through some parts of FO: New Vegas, but since I really oppose gambling, the Post-Nuclear Blackhole Sunset Strip setting really didn't work for me. I also got fed up with about three quarters of the available factions and ended up killing them all accordingly, which made me wish I could lug around full-size nuclear warheads so I could just nuke the whole area instead of amassing a four-digit kill count by hand and small arms. New Vegas isn't bad, I just think Fallout 3 offers a more varied and more fun selection of 'episodes' or sub-plots. I also found the whole main story plot to be quite a bit more coherent and, in the end, more rewarding. Writing that really hurts, but I can't change the way I feel about it.
I take it you're on PC... if you were on PS3, I'd warn you about the constant crashes. Some folks bought new PS3 units because they thought their hardware was faulty, when in fact both FO3 trips kept tripping and acting up.