Heck, if you're going to have visual stuff in there anyway...

Get a plasma. Make sure it has a VGA input and also an anti-burn in mode that can subtley shift images. Find a suitable quiet low power PC to stick in your audio cabinet, and set it to automatically cycle through some arty-farty images. Linux would rock for doing this - run X with no window manager, and have the startup script run xv -root -rm 5 -maxpect -wait 3600 -wloop somedir/*.jpg after X starts.
Find a carpenter to make a nice arty frame for the plasma so taht it looks like a painting hung on the wall.