We have the Kiddy Guard gate- they are expensive (and a bit noisy) but impossible for my kids to open or climb. (
http://www.toysrus.com/product/index.jsp?productId=2267704)
Also, if you do need to resort to a reward for successful attempts- consider stamps (on their hands, feet, etc.)?? Our local Little Gym uses them and the kids all go nuts to get stamped.
I just read a book about incorporating the Montessori method into your home (How to Raise an Amazing Child, The Montessori Way) that recommended that, from infancy, children do not sleep in a crib but instead on a matress or futon on the ground. The entire room should be baby proofed, of course. At least this would eliminate the risk of a fall from a crib for a climber but I don't know if it would work for all kids. I don't think my kids would ever go to bed if I "allowed" them to be out of it ever without permission.
