I haven't come across any decent dark Visual Studio 2008 color themes with support for ReSharper's Color identifiers turned on.
Have any been published?
I created a dark theme that uses the additional color targets provided by Resharper.
It is available for download here. Remove the .txt
extension from the file and then import it into Visual Studio via Tools > Import and Export Settings. This settings file only contains color settings, so it won't interfere with any other settings you may have configured.
Note that I exported this file from VS2010 with Resharper 5.1. It may work in VS2008 (please post a comment if it does.)
Note too that you will have to check the Color Identifiers checkbox in the Resharper options.