Hey, I'll stick my neck out for New Vegas on durability for this one.

Weapon repairing could be an entire build in New Vegas. My last character's build was centered around maxing out the fire rate of pistols and using a handful of specialized repair perks to make 9mm ammo with stupid damage and armor penetration, but extremely overinflated durability damage per shot. I'd come up on a group of raiders, blast out 10 magazines of ammunition, then scoop up all their junk pistols and casings, then dump them all back into weapon durability points and fodder for crafting more junk ammo. By the end of the game I was like some kind of eldritch gun-eater, consuming everything in my path and spitting it back out at horrifying speeds.

It also made the Dead Money DLC on that character hilariously empowering, when the endless supply of broken police pistols and depleted energy cells worked just as well to fuel my horrible creation as decent-quality firearms and munitions in the Mojave.

I can't speak for FO3's durability system as I never got into FO3, but in New Vegas, at the very least, it turned out to be a pretty enjoyable little system.