My favorite is me, Wulf Ratbane.
Character concept: Fighter-thief, low charisma-- and regardless of circumstances, ALWAYS choose the most offensive dialogue option they give you.
I got into a lot of fights.
Since I usually play online with a friend, and he likes to run his own characters, we didn't have much room for NPCs. But by common agreement we would NEVER play without Minsc-- no, not even for the possibility of some hot chick-on-chick action between Ariel and the uppity druid.
Minsc steals the show.
Wulf