I started subscribing to Real Network's Rhapsody about a year ago and I have to say, it has completely changed my music listening habits.
For those of you unfamiliar, it's basically a service that lets you "borrow" unlimited amounts music and listen to it for a fixed monthly price. Their selection is very large, although not as big as that of ITunes. For an additional fee they let you download tracks to your portable mp3 players.
This has allowed me not only to give free reign to the DJ stuck in my head ("Hey, I haven't listened to this song in a long time! And that reminds me of that other song!"), but also very easily familiarize myself with new bands.
In terms of what I am listening to:
Mozart "Cosi fan tutte"
Art Brut "Bang Bang Rock & Roll"
Blow Up Hollywood "The Diaries of Private Henry Hill"
Bruce Springsteen "We Shall Overcome: The Seeger Sessions"
Elf Power "Back to the Web"
Beirut "Gulag Orkestar"
Johnny Cash "Personal File"
Lupe Fiasco "Lupe Fiasco's Food & Liquor"
Tegan and Sara "So Jealous"
Wolf Parade "Apologies to Queen Mary"
XTC "Skylarking"