I remember playing Fo3 after years of waiting and being a fan of F1/2. I really tried to hate it, but in the end I still played it and enjoyed it. It isn't a bad game in itself, it's just a bad Fallout game and gives the previous titles bad rep. I didn't play Oblivion before Fo3 so I didn't feel like it was "oblivion with guns" but later when I played Oblivion, I immediately understood that. For me the best part of F1/2 were the dialogues and the story, fighting was the most boring part and I hated doing new runs in Fo2 because I always had to get through the Temple of Trials. When you are a 12 year old kid, F1/2 is the best thing that can happen to you. It's like a book but an interactive one and you can really get immersed in the story. Actually, it has a lot of features of a book: it has lots of letters, it has a story and you discover something new everytime you read it again.
Dialogues in Fo3 were really laughable, the voice over was annoying as hell too - I can read it 5 times faster than your pathetic voice actor. Bethesda used like 10 voice actors in total in the entire game, but the game had hundreds of NPCs so you would hear the same voices over and over again. They used voice overs only for the really important characters in F1/2 for a reason.
Fo3 felt really shallow. I don't think I can recall a single quest, a single NPC worth remembering. There was a ghoul that ordered you to arm the bomb in a town that built itself around it. I just remembered that and I really had to dig in. The idea of a town built around the bomb is so retarded anyway. It's like they didn't count on a player to figure out what the game is about, "Yeah, we'll put a bomb and build an entire TOWN around it so that our clients know what caused the destruction!". On the other hand F1/2 had a lot of interesting characters and quests, years after playing it I still remember Marcus and miners of BH, Tandi and V15 issues, Chosen One, GECK, Torr and his moo-moo, Gizmo trying to take over Junktown, Harold, New Rano mafia wars etc. it feels like I have read a good novel. Now that I recalled these stories I can say that F1/2 was much deeper than when I perceived it as a kid. Every town had its own interesting story, Vault City made me feel sorry for those living outside the walls (now I know they were rapefugees), Broken Hills tried to portray the struggle of different races living together, NCR which thought of itself as the good guys but that didn't stop them from profiting from slavery etc.
If you think about it, Fo3 really was a piece of shit and a lousy cashgrab.