We use two online music services (three if you count buying CDs on Amazon which we do a lot of).
We use iTunes and iPods for portable music.
And we use Rhapsody for checking out new music before we buy it and also for listening to stuff we don't want to buy.
But I've been listening to Rhapsody more and more on my laptop in the morning while I do email and blog. I've been going back to old stuff I don't listen to much anymore. I've been checking out new stuff.
It's really a great service.