I always mean to, but I feel obligated to choose a color scheme that's pleasing to the eye and end up getting frustrated when I can't put one together. There's always at least one track color that's too similar or contrasting to another.
I color code according to instrument family. Strings are burgandy, brass and woodwinds are gold, all percussion is dark purple, bass dark blue, rhythm guitars blue, lead guitars light blue, piano and organ are green, choirs are aqua, etc...
Drum are orange cause my first kit was burnt orange.
Bass is purple cause it's deeeeep, haha.
Vocals are always blue because my singer has ridiculously blue eyes.
Guitars are green for the TS,
And harmonies are usually pink,
Funny you mention that - I actually do have it, but it would change for every instrument on every song for me so it wouldn't be of much use.
Cheers guys - I already do color code things but its more just for visual separation; never had a concrete system in place but I think I'm going to establish one now.