I like them all, but the most interesting other than Nameless himself is Grace, IMO, followed closely by Morte.
Grace has to be completely unique in that she is a CE creature by birth and instinct, yet she has transcended herself. Fallen angels are ten a penny, but Grace is a risen demon. Add in the fact that she is the cleverest character and capable of genuine insight... Then add the extremely lady-like personality and that beautiful voice they give her... Grace gets my vote easily. The alignment may say LN, but I don't think there's any doubt she's really LG.
I loved Grace.
Grace & Nathyrra (of HOTU) are example of great characters that have an in-born natures of evil, yet struggle to try and be good-natured characters. Grace is a succubus that runs a brothel -- but a brothel full of stimulating conversations! Nathyrra of HOTU is a drow, considered evil, yet she found Elisatrae.
You could kiss Annah, but could you actually kiss Grace? I'm sure the Nameless One might be the only PERSON who could return from the kiss of a succubus, since he is immortal!
I loved Grace's voice -- Jennifer Hale rocked. I believe from what I heard, Jennifer Hale was the voice of Bastilla in SW:KOTOR (which I have not installed yet). Anyone know if that was true?
Oh yeah -- Sheena Easton, the former singing icon, was cool as Annah. I liked Annah -- she was just fiesty. I loved when she said "Pike off!"