I once butchered "Let's Get it On" at a karaoke bar. I mean.. I really butchered it. All I remember was a table of semi-pro karaoke patrons giving me the death glare, as if they wanted to see me disintegrate on stage and have the janitor come sweep me under the door.
This is an example of a great cover because it stays true to the original song. They didn't change it much and try to make it their own, but the accuracy they maintained in spite of a drastic change in instrumentation (produced completely with toy sounds) is impressive. Also note how the singer does his own thing with the vocals, rather than attempt a faux- Michael McDonald voice. He doesn't attempt to do a soulful big-man voice. He sticks to what he knows and it works.