I see that I can install 'myunity', and that seems like it will be overkill for my problem.
Here is what happened:
I was using 2 monitors with different desktop backgrounds using nitrogen, and the unity launcher was colored the prevailing color of my backgrounds (great).
Then, I added a third monitor. When I did that, things got a little screwed up, because I had to unplug everything, plug it back in...and I plugged in the wrong hdmi cable...anyways, got it sorted out; all the resolutions correct...and then got nitrogen set up with a different desktop for each monitor.
Only problem is that now the unity launcher (vertical portion on the left side) is this annoying original ubuntu pink/purple, even though the rest of the theme is silver.
How do I force the unity launcher to take on the right color?
(I found the 'Appearence' section, changed the theme, but no luck)
Here is a screenshot (the wall paper is all black and white; no color):