Already got the game back up and running.
Because yes, my life is that fucking pathetic.
Driver switch-out complete. Game wiped and reinstalled. Played through the tutorial, out through Springvale, and into Megaton. No problems observed.
If it's going to do it, the most I've ever had the game last is fifteen minutes. By sixty, if it was going to it would have, so I can assume I cleared out whatever the issue was this time.
Down side, I'm stuck back on 800x600 for the time being.
Going to start re-adding stuff, try to get the game back to normal, but it'll likely take awhile since I don't want to just toss everything back in. Would likely cause an issue of some sort or another.
Some things I learned during this:
Fallout 3 really is much like Oblivion. Both game are awesome in suitably modded form... and both games fucking suck in their unmodded form.
Textures are garbage, weapons are boring, sky is shitty.
Miss Type 3, miss Fellout, miss my decent weapons and my cadre of sadistic cuties.
While possibly not explicitly caused by, the problem happened very close to my installation of some of NMC's enhanced textures for Megaton and Rivet City.
I think this time I'll be leaving those out, just to be safe. The default textures may suck, but they don't stop the game from working.