Oh, you absolutely MUST get the all the DLC for New Vegas. Old Wold Blues is pure genius (well, Avellone is the genius in question, but that attribute is a given). You should also read All Roads, the prequel comic written by the Man himself.
As for Fallout 4, I'm hoping Bethesda lets Obsidian handle the storytelling (let's be honest, NV is the true successor to the spirit of the classic Fallout games) whilst keeping the reins over design. I can't wait to see the engine they used for Skyrim in all its, post-apocalyptic, glory.