FoFiX supports very costumizable themes. Basically everything can be changed to look like you want it too. Animated backgrounds can be achieved with a series of images, support for video is not present right now but it may come. Right now there's mainly two types of themes, Guitar Hero styled and Rock Band styled.
Most complete themes
myfingershurt's Rock Band 1 theme (Rb-MFH)
Rock Band style, spawned by the works of several developers and artists, this is a rock band clone theme trying to deliver the Rock band feeling as closely as possible.
A rock meter to the left, combo display and overdrive (star power) meter right under the frets. Scores and note streak in the upper right corner.
worldrave's Guitar Hero III theme
Guitar Hero style, worldrave has put a ton of work trying to get this theme to look like GHIII down to the pixel. However since fofix does not support everything needed for that this theme does not look like the game 100%.
Rock meter to the right with star power(overdrive) meter on top, combo display, scores and note streak on the left.
blazingamer's MegaLight theme
A stripped down version of the rock band theme. Only the essential is left, this is distributed with svn checkouts and megalight downloads.
blazingamer's Megalight GHIII theme
A stripped down version of the guitar hero theme. Only the essential is left, this is distributed with svn checkouts and megalight downloads.
death_au's Old School FoF theme
Rock Band style, tries to get the old Frets On Fire feeling back while supporting all the new features.