The key to beating oblivion easily is to take more or less useless skills you'll never need as major skills. That way you can max the shit out of everything while enemies stay low level.
Thats... I never thought of that.
Name a Bethesda game, and I'll tell you how to break it and totally wreck everything.
I'll say morrowind. A rule though, it's gotta be something that isn't common knowledge.
YOu can beat it in about five minutes with some luck, by using little more than the "flying" spell and some potions. It's not worth learning ways to abuse it.