AnointedArcher makes a heck of a point. 45# bows of 30 years ago aren't the same as todays. Modern materials, better manufacturing techniques, etc.
That said, shoot the heaviest bow you can train yourself to shoot well. I used to shoot 65#, but now all of my hunting bows are 57#. I always cringe when folks start the "I killed a deer with a super light bow" threads. So many things can go wrong...use an arrow that is heavy enough, and a bow that is stout enough so when the "gremlins" attack, you don't leave a wounded animal in the woods.