Currently, if the top section in a playlist is expanded, it will show a stash of the artwork from the files in that playlist. I think it would be pretty sweet if you could assign artwork to playlists the way you do to albums (except of course they will not be stored in tags). For instance, if I have made a playlist, burnt it to a cd and made artwork for the cd, I could assign that artwork to the playlist, and it would show in the top setion instead of the cover stash. This contributes to the feeling of the playlist as being something personal and unique, much like the good old actual mix-tapes.
Thoughts?