Count me in as ready to lose about a few hundred hours of my life playing this game. I was oblivious to the Fallout series prior to Fallout 3. On a whim, I decided to give it a shot. I was hooked instantly.
Fallout New Vegas isn't a sequel but another story within the same world of Fallout. Not much info released yet on the game (although there are some rumors that are very likely). More info on the game will come in the next couple weeks via Playstation and Xbox's magazine.
This game has been in development now for around 10 years and they have managed to get to a stage that a single developer could have done in around two weeks. It's a great example of the perils of Early Access.