Received: Christmas Day 2005 (Best Buy gift card, Roady2).
Canceled: Early 2007. Gave the service a chance after Music Lab and Luna went away, but it got collectively worse after that. Once the merger talk started up there was no way I was going to stick around, and won't be returning especially now that Pandora and Slacker exist, and there will be caching on the Slacker iPhone app soon. Which eliminates the 'you can't get slacker out of cell range' argument.
I believe it was May, 2005, so I'm coming up on 5 years. I remember debating over which service to get. I chose Sirius because they had the NFL, Big 12 football, and Mojo Nixon as a DJ. I wasn't a Stern fan, but became a fan when his show started on Sirius.