Yah, dont get the happs lights that go underneath the trackball. I had one for my blue illuminated trackball and it had the exact problem everyone has been talking about, even when I WAS using it, the light is just too hot for that poor ball. It heats up the ball which expands and no longer fits correctly on the rollers. Go with a bright white/colored LED, the color of your LED should be matching with your trackball if your going to go that direction. One super bright led should do the trick, I think mine was like 4 bucks from radioshack.
-Chu