I took my own stab at an icon this morning, after reading Apple's Guidelines. It didn't turn out at nice as anything that's been presented here already, but I decided to post it anyway in case it gives someone with more talent than me any ideas.
http://www.grayproductions.net/ruby/images/TextMate_Icon.png
In my defense, it looked a lot better when I was still playing with it at large sizes in the ray tracer. :) You could almost read the code and you could see the brushed metals. Ah well, it seemed like a good idea at the time.
James Edward Gray II