agree with KISS Alive II versions better than the studio recordings.
Megadeth's "She-Wolf" on Rude Awakening with extended guitar duel.
and not sure if this counts as it is sort of a cover,
but Mick Jagger & Tina Turner doing "State of Shock" at Live Aid rocked, and put The Jacksons original (with Jagger and Michael singing) to shame.
'Hot Legs' live with Rod Stewart &Tina Turner