This
I only finished the FO3 main quest after they patched the ending so you could keep exploring. It was a sad day when I realized i had completed every single quest available Except the radiant ones) and all the DLC so had nothing else to do except roam the wastes dispatching marauding bands of Raiders and Muties which were becoming harder and harder to find.
The only other Bethesda game I completed was Morrowind on the PC version but not the Xbox Version which I also have. I then modded the heck out of it.
Oblivion I ignored the main quest but then discovered that, because of its leveling system and the choices I had made, it was almost impossible for me to complete the main quest.
Skyrim I stopped the main quest when I had to pick sides but have completed all the DLC
In Fallout NV I never completed the main quest as it didn't really grab me, I would just explore and do side quests. I didn't bother with the DLC for this game either. I don't know why it just didn't appeal to me as much as FO3
I know they have already had Fallouts based in California but they were earlier games. I would like to see them do a FO release in the current format based in the Bay Area where there are locations I know well. I kind of knew Vegas and DC as far as Boston goes they could have just made anything up and I would be none the wiser. Obvioulsy those who live in or know Boston probably feel the opposite.