Most overpowered things in games?

[Barozi]

Mummelmann said:
Sneak skill + Bow in Skyrim. Removes all challenge from the game.

Well if you're smart enough (or just read up on the internet) there are lots of ways to overpower yourself in Skyrim.
Sneak, Enchantment, Alchemy etc.

Though if you play the Sneak + Bow combo without trying to break the game (grinding), I think it's not too bad as you don't even get that much experience towards the Sneak skill if you use the Bow. The Dagger though.... oh boy.