Here's what I mean by "whenever I look suspicious" - every time an NPC yells at me for doing something I'm not supposed to be doing (even if I haven't done, and indeed have no plan on doing it), the game crashes. This makes it very difficult to play, as I can't even look at something that isn't mine without crashing. And if Craterside Supply is closed when I get there and there happens to be a settler looking at me, well...
http://dl.dropbox.com/u/5733962/DxDiag.txt. I am not putting it inside the post, because all that would do is clutter it. And New Vegas runs on High with hardly any issues, none of them near as bad as this, so I can assume it's not my hardware, seeing as FO3 and NV run on the exact same engine.