To me, as a singer and a live sound engineer, the very most important thing is ALWAYS--monitors. thumbsup
If they are in-ear you MUST have someone on the monitor desk you trust and will get your mix right--ALL NIGHT--not just on the first song. I have sung with in-ears where the guy drifts and then they are worthless and the best other gear in the world will not make up for it.
If they are wedges, they need to be over-the-top with vocals--I do not care what box it is. When it seems like it is too much, there had better be at least another couple dB of vocals left to add to the wedge(s).
If the singer can't hear themselves, it does not matter what else you have. When they hear themselves, you get the best performance they are able to give at that show--once again, regardless of what other gear you have.
Singers always love my rigs because I make certain they can hear. Sometimes it is as simple as reigning in the other instruments on a smaller stage so the stage volume is not an issue. Plus I always push the higher freqs to make the rig more audible. Yes, I have torched a lot of diaphragms in my days and I always keep an extra 2426 diaphragm for when I push it too far (again
) But that is what it takes for me, for my people, in my experience.
After that, I guess some bigger dollar mic--Shure KSM9, Nuemann KSM 105,.... Gear--it will all end up being the same higher-end stuff for a monitor desk. Really, right? No matter what sound company puts the pack together. And the front of house, well that will really depend upon the guy at the desk and what his (or her) fave rig is if they bring along their own stuff. Some folks that means a lap top and a USB cord for the Yamaha board in the theater at the next stop on the tour. For someone else that'll mean a rack of pres and comps and e.q.s--but in truth I have seen a lot less of the later and a lot more of the former.
A guy I knew who did tours with Clair Bros. (Billy Joel, U2, Rod Stewart,...) told me back when I was getting started: with vocals it is all monitors and with monitors it is all e.q.--tweaking out the boxes. (That was before in-ear.) He said he had a desk and racks of e.q.... parametrics to pull out transients and spikes and graphics to shape the tone. The comps were used to keep things under control. That is how I run my show and it works quite well.