If you need music for DJing, you should not use a program to download all kinds of music, but instead you should listen to all kind of music and download the music files you find adequate in each type.
To listen to all types of music, I suggest the websites listed hereafter, providing music under the Creative Common license: http://www.jamendo.com Enables you to freely and legally download and listen to over 6,000 complete albums. Discover and share talented new artists released under the Creative Commons license.
http://www.dogmazic.net A free music community portal, offering more than 24,201 tracks provided under Creative Commons license, which you can legally download and listen to.
http://www.opsound.org/pool/artist Musicians and artists are invited to contribute their work under the terms & conditions of a Creative Commons copyright license. Listeners are invited to download, share, remix and recreate material.