Napster Offers Enthusiastic Revenue, Subscriber Snapshot — Digital Music News: "For Napster, the AOL Music Now acquisition helped to transform the subscription total completely."
This puts them out front in the subscriber race, followed by (in my approximation) Rhapsody, Ruckus, Yahoo Music Unlimited and MTV's Urge.
I actually don't think the shakeout is done yet. I'm guessing that we will see some more subscriber fire-sales from companies that don't want to invest anymore money chasing customers.