I find myself using a sling less and less for hunting. Used the Harris bipods for years, but lately have settled in on the new "Safari Sticks" from Stoney Point. These can be adjusted for heights all the way from sitting to standing, and make a nice lightweight walking stick when out in the field.

PS: Still use a sling for carrying the rifle - the neoprene ones that stretch a little are great - make the rifle seem a pound lighter.