Here's some info on the lenses we use in our work.
Canon 24-70L f/2.8L II and Nikon 24-70 f/2.8G
The workhorse lenses. They cover a wide range of practical focal lengths from wide to short telephoto and offer the flexibility and speed when shooting on location. Both of these lenses are stellar performers and have a place in any kit.
Canon 70-200 f/2.8L IS II
Part of "The Trinity" -- the ubiquity of these first three lenses in any kit is because they're all exceptional performers, and should be part of your kit. A 70-200 (in any flavor) picks up where the 24-70 left off, and covers a useful range of telephoto focal lengths when you want compression.
Canon 11-24 f/4L
A niche lens, but at 11mm at its widest, the 11-24L offers an angle of view and a perspective that can't be matched. Sharpness even wide open at f/4 is exceptional, and distortion is well controlled. A must for landscape, architecture or real estate photography.
Canon 35mm f/1.4L and Nikon 35mm f/1.4G
35mm is a good all-purpose focal length for general use. It's not very flattering for headshots or close-up portraiture, so don't do it! We use ours for street photography, or environmental portraiture where you want some ambiance.
Sigma 50mm f/1.4 Art
Sigma 85mm f/1.4 and Nikon 85mm f/1.4G
Canon 100mm f/2.8L IS
Tack-sharp and accurate, the 100L Macro from Canon is useful for macro and product photography. However, its long focal length and sharpness is also very useful as a portrait lens, especially useful for studio headshots.