I recently discovered a compilation series on a torrent site where someone had collected together a lot of game OSTs on the PC ranging from the 1990s up to present games. So far I managed to find 3 parts, each about 15GB and there is a lot of great music included.

I also recently downloaded the Shadow of the Beast OST (from all three games) and it seems to be an official OST, not one created by a fan sampling the game, and is really good. I've always been a big fan of the music from that series, especially the first two games.