I have three airport expresses, Bedroom, office, and kitchen. My AppleTV is in the living room. My Mac Mini is in the office, and the ATV is synch-ed to it's music library. The main network, wired and wireless, is provided by an Airport Extreme. The Airport expresses are for music only (one also serves a printer).
I'm in my office. I shut down my mac mini music server, grabbed my ipod touch. Fired up remote app and connected to my ATV. Started playing Dire Straits "Telegraph Road (Live Remix)" from the Money for Nothing Album (this data was displayed on the ipod). No Album picture though..
Switched to a purchased album. Album artwork popped up too.
What other Meta Data is there?