Re: All windows, and panels were accidentally made completely transparent.
Glad you solved the problem, but just for your information, another way to fix this is to have fusion-icon installed and running before you make changes to Compiz. I've done exactly what you did several times, and all you have to do is right click on the fusion-icon and select Metacity as the window manager. That effectively turns off Compiz so the windows become opaque again. Then you can change the settings and turn Compiz back on.
Main: Intel Core i7 920 D0 @ 4.0GHz | Asus P6X58D Premium | 6 x 2GB Mushkin Redline 1600 7-8-7-24 | EVGA GeForce GTX 560 Ti | 6 x 1TB WD Caviar Black | Mint 15 Cinnamon / OS X 10.7.3
Portable: Dell Mini 9 | OS X 10.6.7