The Iridium theme whitens metal and applies a unified toolbar look to all applications including Cocoa, Carbon, X11, and qt/Mac applications.
Iridium's motto is "One look to unite them all and in the lightness bind them!" This has meant that a few features of Iridium have had to be changed in order to fix bugs. And Iridium now has its own installer, no other software required.
Quit all other programs before installing. You will need to logout or reboot for all changes to take effect.