Shot a wedding Monday where I did all the portraits and B&G shots from start to finish with just one lens, my 85mm 1.8, I was shooting in low light and my 24-70L just doesn't sharpen up enough wide open. It was fun eventhough for candid work that 85mm that I once was almost married to has been surplanted for the more petite 50mm 1.4, I've fallen in love with the way a 50mm draws eventhough it's a inferior lens in almost every way.
I shoot weddings with two cameras (FF) on me, one with the zoom and flash, the other with prime wide open. The prime only shots make up 15-20% of the final proofs which is not bad considering what a high percentage of the proofs are taken up by 'must have' shots in the very ceremony intensive weddings I shoot.
Left is 85mm @ f2.8 posed and light fill flash, right is 50mm @ f1.8 candid of the bride in the synagogue just before the veiling ceremony.