We are almost at the point of not having any backline. The only exception is my Puma 110, which goes on a stand so the drummer and I can hear it, but it's not loud enough to affect the FOH mix.
We got this way as a result of a gig in a long thin building, where I couldn't hear my bass amp standing next to it, but it was massively loud 30 feet into the room. We're now at the point where the vocals go through one pair of monitors, keyboard player has a second mix through a floor monitor and the guitarist has in-ear monitors.
Everything goes through the PA for FOH and we have a sound engineer/photographer who sorts the mix out.
I love it. It's totally controllable and has drastically reduced the noise on stage. We have a very quiet drummer anyway, and now that we no longer have a massive valve guitar amp to compete with we go home from gigs without any tinnitis or deafness.