Acid Pro
Loop based music creation tool.
Atomix Productions
Offers Virtual DJ, DJ Box, and AtomixMP3 programs.
Hip Hop Starz
Make your own Rap and Hip Hop. 1100 samples and loops for constructing your tracks.
Jackson, DJ
Mix any style of music and change the structure of songs while you're playing them.
Magix Music Maker
Sample based music creation, also templates for making musical websites and videos.