They are two different games Soprano, Fallout 3 is like Oblivion, but it has a more interesting setting, it takes place in post apocalyptic Washington DC.
Farcry 2 is a shooter…idk…you can only have so many shooters. If you have Halo 3, Gears of War 2 or CoD4/WaW then why get another one?
Then again if you already have Fable 2 or Oblivion you might not wanna get another RPG…
But Fallout 3 is an RPG with First person shooting game play…so you pretty much get 2 games in one…
It’s really just your choice though, don’t buy either if you’re skeptical or not sure…And look them both up on youtube for some gameplay videos and see what you like.