Disclaimer first: I am not professional.
I find the best well rounded lens that does good and very dependable on sharpness is my
Tamron 28-75mm f/2.8. With exception on lacking on wide angle for group shot, the zoom range works quite well as I found the need to go beyond 50mm.
I also have the
Sigma 17-70mm f/2.8-4.5 and I would pick the Tamron over the Sigma for speed. But the Sigma will have the benefit for 1:2.3 close up and the wider angle will serve you well for the group shot need in wedding.
For indoor and low night, I counted on my trusty
Pentax FA 50 f/1.4