best vocal harmonies in rock

Has anyone mentioned The Mamas & Papas? I take them for granted until one of their songs comes on the radio. They were REALLY good!

The thread's heading reads "best vocal harmonies in rock". If we're gonna relax the definition of rock, I'll add the great R & B and Girl Groups of the 1950's and 60's: The Ravens, Billy Ward & The Dominoes, The Clovers, The Drifters, The Platters, The Coasters, The Chantels (their "Maybe" is insanely great, as is Dave Edmunds' cover), The Shirelles, The Crystals, The Ronettes, The Staple Singers, The Persuasions, The Robins, The Swan Silvertones, dozens more. 

The Everly Brothers learned from The Louvin Brothers, John and Paul from Phil and Don. I haven't read through the whole thread, but did see many of the standards. They've probably been mentioned, but I have to say The Beatles were getting really good at 3-part (in the studio, anyway) during the Rubber Soul/Revolver era. The best harmony singing I've heard live (and I saw both The Beach Boys and The Beatles) was that of Jellyfish. Stunningly great!