Well, today NME has published a chart of the "best cover versions of all time".
It's here: http://www.nme.com/news/muse/53090
Virtually none of them meet my criteria for a good cover. In particular, I don't believe that most people will have had any idea that the songs were covers when they first heard them. If someone had to tell you the song you know is a cover, it doesn't count.
( A poll to reinforce - or possibly dispel - my prejudices )
It's here: http://www.nme.com/news/muse/53090
Virtually none of them meet my criteria for a good cover. In particular, I don't believe that most people will have had any idea that the songs were covers when they first heard them. If someone had to tell you the song you know is a cover, it doesn't count.
( A poll to reinforce - or possibly dispel - my prejudices )