I always have a lot of love for the Firefox theme designers that think outside of the box. The Metal Lion 300 Firefox theme does just that.
Inspired by the film 300, this theme has been designed to have a long lasting appeal to both fans of the film, but equally to those who have never seen or heard of it. Whereas other themes of mine have concentrated on gradient and/or 3D effects, this theme explores the interplay of colors and also the use of transparent effects.
Sure it might not be a selection that works for everybody, but I give them bonus points for trying to do something new.