Most of the characters I end up playing on the site are NPCs from my persistent world Pathfinder game I gm with a local group. I always spend a ton of time creating the NPCs, their backstories, genealogies, etc. Seems like a waste when the party blows past them in 30-an hour. As far as characters go that I want to play and have never really had a chance? I've always loved the manipulative adviser trope: a devious court magician who ends up taking over the kingdom through subtle trickery and stabbing the rest of the party in the back at the end. 

EDIT: Didn't notice my super thread necromancy until it was too late.