A band doesn't need to be filled with virtuosos to be great, but there's definitely an added kick to a band that blows your mind with just how amazingly they can play. For the purposes of this discussion, singers/vocalists are musicians.
1. Led Zeppelin
Nobody has ever drummed like John Bonham, Robert Plant had one hell of a vocal range with the ability to shriek or sing gently whenever he pleased, and in addition to playing one mean bass John Paul Jones could play basically any instrument at a very high skill level...their recordings abound with his kick-ass playing of keyboards, mandolin, organ, guitar, recorder, etc. Oh, did I forget to mention a man named Jimmy Page? One of the greatest guitar gods ever, with flair, versatility, creative genius, etc. I love listening to this band baked and becoming overwhelmed by four virtuosos creating magic for my ears.
Eric Clapton, Jack Bruce and Ginger Baker...enough said.
3. Deep Purple
Ritchie Blackmore could pound out riffs and solos with a demonic frenzy, Ian Gillan could really wail, Jon Lord drove it all with some of the meanest keyboards ever played in rock, Roger Glover was a solid bass man, and just listen to Ian Paice's drum solo on "Made in Japan."
4. The Who
My god, that rhythm section!...and Daltrey's voice