or white track with rainbow background
White track with rainbow background is my favorite too now. Or black track with map-of-the-world background. But I found that white track gives black blocks, and to me, those black blocks seem to be better visible. When I'm playing on white track I pick up trice as many blacks as whites on black track.
It does make a nice change, I've played tracks a few times that way. Would be nice to be able to change track colour independently to background colour.
I once edited a background file so that I had white track with black background, but that way, my minimap was invisible, that's one of the reasons why I know use rainbow, just like Pyritie. The other reason is the black blocks (see above)