It’s still in its relative infancy, but all the artwork is HQ 1000px and must be approved before it’s submitted. It was started as another repository for XBMC artwork and is growing pretty quickly. Music stuff uses musicbrainz IDs, but unfortunately it uses the Release Group instead of the actual Release, but it still offers a decent collection.
The API key can be found at the very bottom.
Of course, you can manually add this artwork. And if any of you have something to contribute, throw it up there.
*I am not affiliated with fanart.tv, just been using it heavily with my HTPC and I figured it may be of use to Jaikoz. 8)