For good old old-school demo/scene/etc music on your N900, install mod-support. Now with proper metadata extraction so the media player will show you titles (and creates a fake artists/album so all your mods go nicely into one "Album" for easy separation from those silly mp3s :)
Latest version is waiting to get built, should be available soon in extras-testing. Please vote on it so it gets into proper extras.
(While at it, I upgraded the libmodplug package and built it with proper optimizations and optification)