Damn if I understand such things. Crashes for me very rare about two or three month already, but I can't just ignore peoples, which say another things.
I can't understand why the same mods on the same version of the game can provide such different results in different systems. Mod work through engine and engine must handle all hardware and software differences, but it seems to me- it is not applied to the Fallout
Fallout has such a screwy and unstable foundation. Even the slightest little thing can cause it to crash. For me, I was crashing constantly when looting or wandering the wasteland, but running the game in windowed mode in 1680x1040 *seems* to have fixed it, which suggests to me hardware conflict with my ATI radeon Hd 4850, even thought the drivers are up to date. I say seems because I've had bouts where it wouldn't crash, but then suddenly start back up again at random, for no apparent reason. But so far, no crashes *knock on wood*
Seriously, this is the only game I've ever played that has given me this much trouble. Bethesda should have made a proper engine instead an add-on from Oblivion. Here's hoping they do it properly with Fallout Vegas. I have my hopes up for that one, because some of the original Fallout team are working on it. And frankly, if you've ever played any of the older games like fallout 1,2, planescape torment etc, you'll know that those guys really know how to craft an immersive and memorable experience. Not trying to knock Bethesda's efforts, I think overall they did quite well, it's just really hard to compare to some aspects of the earlier material (graphics aside, which we can all agree are better than the older games).
Edit: Also forgot to mention - mods like FWE actually make the game worth playing IMO.