You can make the case that a dollar is a fair price, since it lets you play the music on an iPod, computer, home audio system, etc.
On the other hand, I see the price coming down as distribution channels increase, i.e. downloading songs from the digital jukebox at the local bar or a kiosk in the mall or giveaways with retail chains -- buy a pair of jeans from Old Navy and get two free songs -- that kind of thing.
anyone can make the case that a dollar is a good price, but I'm just not buying it;-)
MP3s may work for pop music but for serious music (a 100 piece orchestra), the nuance isn't there. I'm sticking with CDs for that genre.