Female. Even though I'm male.
Out of all new NPCs in KOtor II, I liked Atton the best. I did never like Visasor the Handmaiden. Their personalities are so... unnatural to me
Anyway, Atton is a lot of fun and the interaction with him is just better when you're female. Additionally, Mical had a few interesting things to tell (apart from that I can't stand him).