The best packaging for a CD has to be Sisterworld, I've never seen anything like it before.
http://www.modo.co.uk/liars-sisterworld

For originality, Oasis' Cigarettes and Alcohol cassette single
http://www.flickr.com/photos/ebotunes/358889965/

My favourite vinyl is Oracle just for the artwork
http://www.anemptygun.com/journal/?currentPage=5

So what are your favs?