I would love to see the music downloadable in the Game Goodie section.

Both the Nine Inch Nails tracks by Trent in the main game, and the other music in the expansions. (My expansions are playing the main game music in Darkplaces instead of the normal ones)

The original soundtrack was included in the initial release of Quake on GOG, but they were forced to backpedal thanks to year-old licensing issues. If you're savvy, you can rip the soundtrack (in CD quality, no less!) from the disc image file included in the package. There is a sticky with a fan-made utility to rip .ogg files from it.