A Gnome Rogue named Katnip (D&D 3.5).
Her weapon of choice was a crossbow, and she couldn't hit the broad side of a barn, but boy could she make money. She would make more gold in one session than the rest of the party would make in a level. Very dry and sardonic, and she never volunteered information unless it was urgent. For some reason, she was almost always the one to happen across the plot-important clues, which of course all of the players (but none of their characters) would hear, and then be annoyed when she didn't automatically relay the pertinent information when we regrouped. I was already an experienced free-form forum RPer at this point, so I was pretty comfortable staying in character, but some of the people I was playing with were less experienced, and they couldn't understand why my anti-social gnome wouldn't tell there characters all about the story she overheard while pick-pocketing people in the market XD . Good times.
Coincidentally, in the game I am playing now, which has most of the same players, my character is once again the only one in the loop. (This time she was sworn to secrecy.) My fellow players are going to kill me XD .