I want to be able to download an entire CD at one time, rather than downloading each track individually. Also, I have Apple, so it has to be compatible with the Mac OSX operating system.
I recommend uTorrent for BitTorrent downloads and Frostwire (conventional P2P) for everything else. They are both available for use on Mac OS X.
BitTorrent files have to be downloaded from a source like The Pirate Bay, http://www.thepiratebay.org
Frostwire has a built-in search engine.