This is more of a "fun" topic I suppose. I really like how you can change the over all color palette of Sonar. Along with being useful for just seeing different things, I find it helps with inspiration from an artistic point of view. 
 
Does anyone aside from me change the colors just to fit the mood of the song that they are making. For example, if I'm making a song that is suppose to feel cold or icy, I tint everything a kind of blueish color. I know it may seem a little OCD, but I just find it kind of cool. I think you can add wallpapr too so nt sure. 

Hadn't thought about it that way, but I do use colors that I associated with sounds. For example red is the lowest-frequency light, so I use it for bass.

I try to use the same colors over and over again because I am trying to identify certain types of instruments.  Like Craig, I use red for bass and I use brown for drums for example.  I might lighten or darken the shade depending on if it's a bus or maybe in the case of a percussion instrument.  That way I know which family it's in but I can see the slight differences in color to give me cues that it's different in some way.

When I'm in FL I do use colors to identify certain things as well. (Greens are mostly always pads and blue for me is bass. Not sure why, basses just seem blue to me. xD 
 
I do a lot of music for multimedia and games, so to draw inspirataion for the environment or situation, I try to color things that way too. If I'm doing a collab, I'll try to organize things a bit more so they make sense.