"I Heard It Through the Grapevine" (Gladys Knight & The Pips)

Okay, I'll probably get hate mail for what I'm about to say.
I don't care for Marvin Gaye's version of "I Heard It Through the Grapevine."  It has less to do with Gaye's performance and more to do with the backing track.  The campy strings.  The cheesy background singers.  The tom-toms.  It's gimmicky, and it sounds dated.
But I love Gladys Knight & The Pips' version.
Funny thing is, writer/producer Norman Whitfield and writing partner Barrett Strong wrote the song with neither artist in mind; they wrote it for Smokey Robinson.
In fact, Robinson and The Miracles first recorded a version of the song in 1966.  But Motown head honcho Berry Gordy felt it was weak and refused to let it be released.  (They eventually cut a different version in 1968 for the album Special Occasion.)  
So Whitfield and Strong went back to the drawing board and came up with a new arrangement, which Whitfield recorded with Gaye in 1967—a session that almost ended with a fistfight, according to music journalist David Ritz's liner notes for The Best of Marvin Gaye anthology (1995), because Whitfield kept needling Gaye to sing in a register higher than he was comfortable. 
Anyway, at the time, Gordy rejected that rendition, too.  Didn't feel it was single-worthy.
So in mid-1967, Gordy was itching to put out a Motown single to rival Aretha Franklin's "Respect," which was burning up the soul and pop charts.  That September, Whitfield and Strong came back with a funkier, gospel-influenced arrangement of "I Heard It Through the Grapevine" and gave it to Knight.  Who promptly sang the hell out of it.
Her read of the song is completely different from Gaye's.  Whereas he sounds torn between love and anguish, she's a woman with a purpose: she's out to confront her man and give that cheating so-and-so a piece of her mind.  She's hurting, but she's going to make darn sure he leaves hurting, too.
The backing track is also superior in every way.  It ignites the moment you press "play" and doesn't let up for 3 minutes.  Funny thing is, the same musicians (Motown's "Funk Brothers") play on both renditions.  For instance, bassist James Jamerson's presence is felt in each instance, but his playing is so much more lively here.  Just listen to the leaps and runs that he plays on every chorus.  It's pure church.
In the end, Gaye's version became the bigger hit in October 1968 when it was released a few months after Knight's version.  It actually was Motown's biggest selling song to date.  
But she still did it best.