I think with the direction the Fallout games are going, it may eventually be its own genre. Possibly called a survival sim.
Just wait for games like FO:NV developed for the direction Wii, Move, and Kinect are taking us.
Imagine the Fox News specials three to five years from now. If the sides of alien boobs and the ability to kill virtual Arabs with a controller got them upset, wait until you can walk around a wasteland, or similar open world, move your hands to weave spells or lop off heads, or even CARESS alien boobs. They're going to have to hire a whole news team just to devote five days to complaining about it.