Change Finder window graphics back to the more visible Snow Leopard ones?
Short answer: Install Snow Leopard.

Long answer: The only way I can think of is a pain.

The images used in Finder's UI are stored in the Resources directory of the application package.

Navigate to /System/Library/CoreServices/Finder/Contents/Resources/

You can find the offending graphics that don't suit your taste and edit them directly.

After modifications restart Finder using the following command in a Terminal window:

killall Finder