The Fallout games crash a lot, they are buggy games, I didn't have too many problems with Fallout 3, but New Vegas I had to save often because it would crash on me after an hour or 2 of gameplay. Funny though the PS3 version crashed more than both of these lol, anyway. A little more info? How, when, specs, how often?
Darn thing was bugged to hell, did it a lot of the time when I was playing it. A few updates and patches sort of fixed it. But it still sometimes crashed out. Great game, shame about the crappy coding of it. Part of the problem. Sloppy coding no doubt, or being lazy taking the short route and porting the code from one device to another say a PC, to Xbox 360 causes this. Instead of direct coding for the device. They do that to save time and cost on production of the game for different formats. Leaving sloppy loose code leading to constant crashing, take a look at porting games to another format. it all becomes very clear loose coding.