Say Goodbye is the only one that really comes to mind as blowing the studio version out of the water. Otherwise, I appreciate both live AND studio versions of most Mac songs. For instance, I prefer the live Go Insane, but the kooky studio version is endearing as well. Sisters Of The Moon is Fleetwood Mac's paramount tour-de-force live song, but it's also a brilliant studio track. The studio production of Say Goodbye is just plain awful, but it's a heartbreakingly beautiful song live.
