Actually by Gladys Knight, though it's been pointed out yo me by one pedant before now that Marvin's version was recorded first but sat on the shelves til after the GK one was released. So you could say it's the original one.Heard it Through the Grapevine (though maybe not actually better than the original - which was by Martha Reeves I guess so you could in fact say Marvin Gaye's version surpasses the original)
What else? Aretha's Respect obviously, Roberta Flack's Compared to What, Patti Jo's Make Me Believe In You.
This is originally a Bee Gees song. I've never heard it, but there's no way it's as good as this.
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/n3FxR2s7VO8?fs=1&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/n3FxR2s7VO8?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>