probably the biggest selling cover was Whitney Houstons "I Will Always Love You", which is a Dolly Parton song.
I have an mp3 of Bruce Springsteen and Jon Bon Jovi doing "Come Together", it's ok.
No Doubt likes to do covers..."OBla Di Obla Da", "It's The End Of the World (as we know it), etc...
Phil Collins had a big hit with his cover "You Can't Hurry Love".
nobody even tries to cover Pink Floyd or Led Zeppelin...for good reason.
I have an mp3 of phish covering "Somewhere Over the Rainbow"...blech..and "Rocky Raccoon"...double barf.
Cruel Summer was covered pretty well--bananrama then ace of base.
banarama covered "Venus".
Rod Stewart had a big hit with his cover of Van Morisson's "Have I told You Lately".