My bows range from 40 to 70 pounds. I like shooting 50 to 60 pound bows the best. Fred Eichler has taken every species of North American big game with a 54 pound bow, so you really don't need any more if you can shoot well.
For hunting here in North America, I personally prefer about a 55 pound bow. Unless you are going after grizzly (including brown) bear or going to Africa, there is not a particularly good reason to go above 55 pounds, but if you can draw 60 pounds and shoot a bow of that weight accurately under all situations, then go for it if you want to. For African big game up through cape buffalo you need to be thinking of a minimum of around 70 pounds.
I can shoot an under-50 pound bow for a couple of hours straight. I am ready to stop after an hour or so straight with a 55 pound bow. At 60 pounds I am good for half an hour or so. At 65 pounds I can shoot for half an hour, but I have to rest some along the way. At 68 to 70 pounds I can shoot for maybe 15 minutes before my form starts breaking down and my shots start getting erratic.
For hunting from a standing position where I would only shoot one or two arrows, fatigue or inability to properly draw a bow up to 70 pounds is not a problem for me. But for target or field archery where I am going to be shooting a lot, or when hunting from difficult positions in cold weather with bulky clothing, I want to be shooting a bow that is 60 pounds or less.
I sure understand the people who think shooting a 45 pound bow is more fun. I shoot a 50+ pound bow better because I get a cleaner release, so that is more fun for me. I don't shoot my heavy bows a lot, but I am glad I have them when I do want to shoot them.
For some people out there, 60 pounds is a light bow. A few guys can easily shoot an 80 pound bow. I wish I were that strong, but I definitely am NOT! I have been buying some lighter bows for when I am older and can't pull the weight I do now. I am 57 now, and those days are going to arrive before I know it.
Allan