I have to go with the flame, because it's quite striking and compliments the whole Interstellar Buccaneer theme. Very charismatic.
Mushi is a neat one, and they are all very original. Personally, I like my avatars to be people, something that could literally be an avatar of me. However, I also like seeing other people's avatars, and am in no way opposed to avatars that are scenes, logos, emblems, or even text.
Whatever you go with should definitely represent some aspect of your personality.