A Look At The Top 6 U.S. Music Download Stores
A sample purchase of 10 rock, folk, country, and classical albums including six recent releases and four back catalog showed a distinct difference in the purchase price of tracks.
SELECTION - According eMarketer in January of this year, iTunes had roughly 11 million tracks, Amazon sold 10 million and Lala offered 8 million. Rhapsody, eMusic, and the Zune Marketplace each had 6 million tracks to choose from. (via ZDNet)