Number one is wizard. My all time favorite character is a human wizard, a former Aes Saidar of Cormyr, currently evil thanks to his lust for power and reading a Tome of Evil. Wizards tend to use thought over brute force, which is my preferred mode of operation. That’s not the same as being passive, however. He prefers to act rather than endlessly discuss possible actions and had a habit of wandering off. It got him in trouble more than once.
Second favorite is probably warriors in general. Just because I enjoy opposites, I will often play a warrior character who will let others discuss and then bash when the time is right. Though, come to think of it, my warrior characters would often get bored and wander off as well. Maybe it’s just me?