These weren't bad. I was just messing with this last night. The only thing I'd change about Sonar's color setup is to make it possible to create a custom track class that's selectable on a combo box in the Track Properties dialog.
For example, I make all of my drum tracks red, bass blue, piano green, guitar yellow, brass orange, vocals grey, etc. I then invert the foreground/background colors depending on if it's an audio track or a MIDI track.
It would also be nice if they allowed you to use a texture graphic instead of just a color. I mean, who WOULDN'T want to make their Track View background a graphic of train tracks? And who wouldn't want a nice chrome look to their piano roll view keys?
I can't complain, though. I'm content being able to assign custom track icons and colors.