Who uses a fixed power hunting scope for hunting? Which one?

If I were going to buid a 100 - 350 yd hunting rifle today, I think it would be a Savage in 308, 280 Rem or30'06 AIwith a 6x scope on it. It would be nice if the scope had a 300 and 400 yard line in it also. I'm thinking this would be for western walking hunting of Antelope, Deer and Elk.