I have a Zune Pass, and love it!
But i think the one thing that would make it better is better music discovery features.
Before I got my Zune I was a member of the Urge service, before Rhapsody killed it, and the feature I loved on it was the dynamic playlists.
It was awesome to be able to fine tune a playlist to find songs i liked, based on mood, newness of track, and popularity of track, and it would update everytime i synced my device... if Zune Marketplace incorporated that into the Zune Pass service, it would make the device even more perfect for me, but it won't be absolutely perfect until audible.com support is added!
ANother thing the Marketplace needs is TV shows and movies... it wouldn't hurt if they were made available via the Zune pass either :-D
thanks for wanting my input..
stephen