Jarlaxle is, in my opinion, the coolest character in R.A. Salvatore's Forgotten Realms novels.
Jarlaxle, a charismatic, resourceful, cunning and sly drow warrior, is a long-time leader of a mercenary network called Bregan D'aerthe. The group is one of the things that keeps the city of Menzoberranzan from collapsing into total chaos. He is also remembered for increasing Bregan D'aerthe's influence to the surface world (Calimport, specifically). In "Servant of the Shard", he gets diverted from the leading position; I've not read anything after that so I don't know how things work out.
Jarlaxle looks quite unusual. First of all, he has shaved his hair off completely. And he wears a hat. Yes, a hat. With a biiig Diatryma feather on it to make it even more outrageous-looking. He has a red eye patch, but it's over different eye almost every day. He has a shimmering multi-colored cloak and boots that either make noise or don't.
He carries quite an unusual amount of magical trinket with him, everything from rings to even subtler things, and it's not even at all obvious what stuff he does is magical and what's not. He's definitely enigmatic, and that makes him even more dangerous than he really is. He has quite a flashy and impressive fighting style, but that's generally just to fool people to think he's really an ineffective fighter when he isn't. His preferred weapons are the daggers he carries with him - they're magically enchanted to return to him after being thrown.
Jarlaxle does things that he has to do and not much beyond that - he's not evil for evil's sake, just nasty enough when nudging things to his preferred way.
(Oh, and in game terms, from Forgotten Realms Campaign Setting 3rd ed: NE male drow Ftr17. I don't know of the rest of the stats in D&D3e, though.)