To the exclusion of all else...

Nearly!

Initially it was Oblivion (GOTY) - 6+ weeks solid, "road tested" all DLC (except the, to my mind, pointless Horse Armour). Used all add on houses even with a good character - had uses. Eventually realised a set of "Chameleon" armour (5 DIY 20% Enchanted items) with my 100% Sneak did make life easy. Taking a brief (very) break during this time I tried Fallout 3 (GOTY) and quickly reverted to Oblivion.

I gave Fallout 3 another try and have now put in around 200 hours (or so) between characters. I did manage to get a "Very Evil" rating on one which has now managed to reach "Good" or at least close to it. I have been trying out various sidekicks...

Falkes for Good - Gatling Laser... need I say more?
Charon - Not convinced really.
Clover for Evil - Permanently bored. Needs decent kit and Stimpaks to survive. Warming to her!
Dogmeat - Great. Uses more Stimpaks than me. Talk to see if they are needed.
Sergeant RL-3 for Neutral - Pulse weapon. Nice one-liners. Tends to set vehicles on fire... time to run!!