I'm a huge tracker music fan, I didn't know about the Deus Ex OST. My introduction to tracker music came from Epic games like One Must Fall 2097, Epic Pinball and Jazz Jackrabbit. It's really interesting to open a lot of these tracker music files up and play with the samples, have a look at the comments left and marvel in the way the music works.

Some other good sites to look at:

http://modarchive.org/ - huge tracker music archive site

https://www.scene.org/ - demoscene information and archive

https://pouet.net/ - demoscene information and archive