I've been wanting to use this gameboy palette I made for awhile.  It involved finding a picture of a brick gameboy with a display of Tetris on the screen and pulling the colors from that.

I did this because most Gameboy palettes are more sepia toned than the puke green display of the brick gameboy.  This is not a definitive palette though for various reasons.

Higher contrast version here: http://img198.imageshack.us/img198/2871/aherobothhighcontrast.png

Also, I experiment with dither in this piece.

EDIT: Thanks for the positive comments.  I decided to make a minor update.  The "high contrast" version is still old.