I like it, but you might want to consider using the Samus in her armor, and showing more than just the face. I like that cartoony look, it's refreshingly new. Though most of us have cartoons in our sigs, that one looks more cartoony (like Bugs Bunny cartoony).
IN OTHER WORDS. It's nicely done, but I wouldn't do a headshot with Samus unless she had her armor on.