Don't forget Sail Away by Deep Purple from Burn (1974). It's the best track on a strong album, consisting of a duet between David Coverdale and Glenn Hughes, which makes me wish that the latter took all the lead vocals during the post-Gillan/Glover period. I say this despite Coverdale being a reasonable singer. There is a remastered CD of Burn, which has not one, but two versions of this great song. Play it loud!
Deep Purple - Sail Away - YouTube