Most (newer) 60 lb. compounds are plenty for any North American animal you would want to hunt, providing you make the proper choice of arrow weight and broadheads for your intended quarry.

Too many "ifs" for me in here. 60 lbs. is PLENTY!!! No matter what your poundage, tune the bow, shoot the right arrows/broadheads and practice, practice, practice!

The "older" slower 60 lb. bows would flat punch through big game just the same as today's bows. Speed is way overrated.

Eventually move up to 65 or 70 if you can pull it comfortably

60lb to 65lbs is plenty, a big misconception is everybody thinks they need to max thier bow out at 70lb, if this is to prove something i dont know, but you need to shoot where you feel comfortable, 60lbs is plenty when it comes to deer, elk, bear, tournament shooting or what have you,

I shoot 60lbs. Although 60lbs today is a lot flatter than 70lbs pounds was 5 years ago. I hunt with guys that shoot as little as 50lbs (they're older guys) and they have no problems at all.

I like Couger's response, speed is way too much overrated. I videotaped my girlfriend shooting and killing a whitetail buck, severely quartering away at 25yrds. She was shooting a compound bow set at 43lbs.

The most important thing in bowhunting is being able to consistantly put the arrow in the boiler room.

Find a pull you could easly pull under the eyes of a buck trying to find movement in the tree you are in and hold that wieght while he is looking at you.