You don't have to play both of them. At least they don't have an intertwined nor a continuous story. I'd say it's more about what kind of an environment you'd prefer. Fallout 3 is a huge wasteland, with a few partially destroyed cities, it's a bit darker, you're somewhat freer to wonder about. Fallout: New Vegas is a desert, with everything very Western, there are casinos, a bit more non-playable-characters, you're a bit more restricted by the surroundings, quests are a bit more easier to find.Isla said:I'm not sure what the difference is. Well obviously I know they're different storylines but I don't know which ones better or if I'd have to play both of them to get the meaning of the over all story.benzooka said:I think you're actually meaning Fallout 3 or Fallout: New Vegas with Fallout. And as far as I know, there are a bunch of Halo's as well.
I'd recommend Fallout, whichever you're meaning.
So, Fallout 3 = wasteland, Fallout: New Vegas = desert.