when I first started playing with arduino, one of the early things I did was to change the skin for the IDE, I like neon like colors on a dark background, the ide is washed out to me (a little hard to read, but I have crap eyes and worse monitor on that computer)
anyway, I was thinking about writing a little application that allowed you to "edit" your preferences.txt in a little gui so you could recolor any way you wanted, but never got around to it
but since were pitching ideas, it would be cool if that info was moved out of preferences.txt and into a proper 'theme' system, ie like notepad ++ just point it to a valid xml file and your good to go