Death - Their last 3-4 albums are not Death metal.
Gentle Giant - For being one of the most complex and inaccessible prog bands of the 70s, their music is funky as hell and great to dance to.
ELP - Even though Keith Emerson was the mastermind, primary creative force and visionary behind the band's music, his keyboard playing wasn't all that great. From a purely technical standpoint, he might have been the weakest musician of the 3. Emerson's ideas translated wonderfully to the big sound of the Hammond Organ, but some of his limitations became apparent when he moved to the piano.
Led Zeppelin - The incredibly heavy rhythm section of Bonham/JPJones actually stymied some of Jimmy Page's attempts to experiment with other musical forms. Much as I love Houses of The Holy (possibly my fave Zep album), D'yer Maker doesn't sound like reggae and The Crunge doesn't sound funky.