It really does depend on your style of hunting.
I have been glassing and scouting for some years and I have settled on a pair of Zeiss 10x40 Classic's for most everyting I do. For glassing you want a good quality binocular that eases eye strain, is comfortable to hold while glassing and for me easy to carry.
Glassing is a bit of an art form that requires practice and some patience. You will find with a good pair of 10x binocs you can spot elk, deer and sheep sized critters within a couple of miles if the conditions are right. You may be able to see more detail at much higher magnification, but typically your field of view is cut so it is not really practical and you certainly don't usually see more. Practice glassing. Plan your glassing so you won't have to be looking into the sun. Get comfortable - sit and rest the binocs on your chest or knees or find a rest that makes nothing get tired. Do the same thing every time. I start by glassing quickly and checking obvious and easy to see places like skyline, edges of timber and nearby areas where animals are likely to be and easy to see. I then begin a pattern either up down or back and forth. Look an area over while holding still with the binocs then move them to the next area - repeat. All it takes is one tree, bush or boulder to hide a critter and all it takes is one opening to find them. You can tell when you are doing well if you see small animals, marmots, birds, squirrels etc.
I also have a Zeiss 20-45x60 spotting scope I use when I am hunting where I will need detail (like sheep, goat or trophy hunts) or when I am guiding. Typically I only break out the spotting scope when I need more detail on what I have already seen when glassing.
These items fit my style of hunting which is a little more portable than many long range hunters.
For those who hunt strictly long range and don't do as much hiking, larger optics (Big eyes) on tripods can be more helpful.
I know a guide who carries Zeiss 10x40 when walking and has a pair of Leica 12x50 for the truck. The Leica is very nice but I would not want to carry them more than needed.
Wish I had a bean counter that said I needed to spend more money on optics.