In the long history of rock-and-roll song covers, the only time I can recall ever liking a cover more than the original is the Phil Collins version of "You Can't Hurry Love". (The Supremes did it well, but Phil's version just...well, it "bounces" better.) And some covers are just-plain-ill-advised: Michael Bolton's "When A Man Loves A Woman" and the Guns-n-Roses "Live and Let Die" leap to mind.
But for the life of me, I never ever thought I would live to see Dolly Parton do a cover of "Stairway To Heaven"...but guess what? She has, in fact, done just that. No, it's not as good as the original. But no, it's not a disaster. The sound is actually intriguing. She's emphasized the song's elegiac qualities and given it a folk-style treatment. Parton has actually put some thought into this. Listen to it here.