I can speak to Nobilis: I played in a campaign for that one. Nobilis is a very interesting diceless RPG system expressly designed to handle characters that can break reality itself. It does so in large part by having the players deal with the consequences of said breaking, rather ruthlessly. To give an example: I have tendencies towards power-gaming, so when I joined the campaign I decided that I would take over the world. I decided to start with China, so I had another player change the universe so that I had always been the Emperor of the PRC*.
:pause:
Yeah, by the end of that campaign I had abandoned the thought of taking over the planet. The crap that I was suddenly dealing with; good roleplaying fodder and entertaining, but a sharp lesson nonetheless in the difference between having enough power to change things and having enough power to maintain those changes. Very salutary.
Check out the Bundle of Holding, in other words.
Moe Lane
*And oh, but did I start making changes right away. That part was fun.