My copy of Fallout: New Vegas finally came yesterday, and I've been playing it for a few hours with random CTD during that time. It seems to be happening when I'm just wandering the wastes; not in any particular place, but it's always out in the open rather than entering/exiting a location like many people have had.
Update: Seem to now have crashes with Dead Money when trying to enter/exit an area. At first disabling the Motor Runner helmet fix got rid of it, but it's happening again now. Will google, experiment and post something if I fix it.