1: If we are talking about pre-existing characters that others have played in games we have either run or been other players then hands down my favorite is a gnomish Rogue player by a friend of mine over Fantasy Grounds a few years back. His name was Nimble Bottomship, a gnome of the atypical WoW variety. He loved to invent and justified his thieving ways as funding his research into creating technology that could rival magic! He was a fun character to have on the team as he offered a mixture of levity to almost any situation and could also be down right scary. Nimble had absolutely no moral compass (He was played under the force of Nature idea of Chaotic Neutral) and his player would actually use a coin to determine every thing he did. Heads = Good, Tails = Evil. It was like playing with Two-Face of Batman fame.
2. A Character I would like to play at some point in the future: Honestly, when I play instead of being the referee or Dungeon Master I typically play the same type of character (see Ghim from yesterday). However, for the sake of the challenge I will admit a passing fondness for the Witch class from Pathfinder, and would enjoy playing one of those in a very dark ages kind of way (in that she is a rare breed and feared by all).
Well, it is Monday and daughters must be prepared for the gauntlet that is school.