(Looks at my CD collection)
Beatles: Abbey Road (and half counts McCartney's Band on the Run)
Stones: Hot Rocks 64-71, Sticky Fingers, Exile on Main Street, Some Girls, Goats Head Soup, It's Only Rock and Roll
Add to TUP's comment about Yoko back-up warblings, Paul let Linda sing too.
Stones by a landslide.