This simple mod replaces the synthesised Star Wars: Empire at War music with Orchestral John Williams Star Wars Soundtrack to suit the occasion.
I found the synth to be very jarring and that it stuck out against the beautiful Williams music, so I set about replacing it all with better music in as unintrusive a way as possible.
This mod is compatible with both Star Wars: Empire at War as well as the expansion Star Wars:Empire at War: Forces of Corruption, install to the same place and it will update both.
To install simply extract the folder and place it under Star Wars Empire at War/GameData/Data/Audio. You may need to create the Audio folder. Once there the game should read from it automatically and play the new music! To uninstall, simply delete :)
List of changed files:
Forces of Corruption
For Forces of Corruption music replacement (which needs it far more) you'll also want to download the FoC Music Mod.