Via James I found out about Clutter and what can I say - wow!
I've had it running for 30 minutes, and look what I've done to my desktop already: (you can also see my appalling music tastes here - mostly rock and punk, a lot of chill out stuff and some musicals)
I can now just double click on any album cover and get it playing instantly.
I only wish it had a preference to 'automatically copy CD cover to iTunes' as I want it to slowly put all my covers into iTunes as it finds them. A truly neat little application.
I set the pic as my desk background:-)