Hendrix,
All Along The Watchtower
http://www.coversproject.com/
There is an amusing Carpenters tribute album with covers by Sonic Youth and Shonen Knife.
http://en.wikipedia.org/wiki/Carpenters
A tribute album, If I Were a Carpenter, by contemporary artists (such as Sonic Youth, Shonen Knife, Grant Lee Buffalo, Matthew Sweet, and The Cranberries), also appeared that year and provided an alternative rock interpretation of numerous Carpenters hits.
Ween covers everybody. Flaming Lips too.
Pat Boone sings heavy metal standards:
http://www.geocities.com/TheTropics/9325/patmetal.html