Fallout 3? That game is ew. Graphics wise. I played it, but the graphics are so monotonous (Brown, grey, more brown) that I had to get mod to add plants. I also custom-modded the music because it sounded like they recycled the music from oblivion.
Survival CrCIA Z is good but dosn't seem to work on newer windows installations. Completely free roam.
Fallout New Vegas has a good storyline, but gameplay can sometimes get boring.
I am Alive is simply amazing. It is kind of free roam, but you still have objectives.