i pretty much buy anything bethesda (fallout, elder scrolls...) or obsidian (KOTOR, alpha protocol...) puts out. i haven't been dissapointed yet. on this site, the monster's den series is awesome. it's simple and definately makes the nerd in me smile.
Oblivion. The whole oblivion vs fallout 3 thing just comes down to which type of world do you like better? Post apocalyptic America with guns and explosions? Or fantasy world with monsters, magic, and sword fighting? Although fallout 3 definitely fixed some of the problems with oblivion. But I also feel Oblivion had a lot more customization(races and classes) and choices in types of characters, while in Fallout 3 it was just good, evil, or neutral.
Fable Dragon Age (based by ratings). And World of WarCraft (lore and it's better than other RPG's).
There is no point in comparing either of these games due to their very extreme difference in playstyle, I'd have to go with: WoW - Lore Fable - Constant changing mechanics per game allowing fluid and ever-fun games Dragon Age - Gameplay