If the reason why you don't want to GM is because you enjoy playing your character so much then not playing an RPG at all seems like a poor solution to the problem!
Other than one of the GM-less games already suggested, you could look at using the Mythic GM Emulator (link). This would allow your group to all play and the emulator will create situations and challenges for you. Some prep will still be needed, but everyone gets to play.
Or you could try Ars Magica (link) which involves 'troupe' play. In this style of game, each player has several characters, and the role of GM rotates between players each game, so whilst you will GM some of the time you still get to play your character on a regular basis.
