As foster parents, we are NOT allowed to spank, so we have to come up with alternatives.
a 16 month old is exploring - sounds like a very smart little guy. However, you are giving him too much control over you (by saying "if we wants something, nothing will stop him").
I keep my younger kids busy by letting them "wash dishes" (which is actually playing in the sink with water and plastic dishes). Time outs don't work, but ignoring him will. At that age, we really need to be with kids at all times - to say "no - that might hurt you", or to pick him up and bring him into a different room.
Climbing kids are really a challenge. Check out some helpful suggestions at www.disciplinehelp.com. Without knowing what is in your home, what you've already tried, and what you're willing to do, it's hard to make suggestions.
For climbing kids, I would highly suggest a playroom where there are soft mats and nothing major he can climb on. Then, if he climbs in other rooms, you can bring him to his "safe room" until he learns not to climb. However, I know this would be very difficult in our small home.
You will NOT raise a terror if you don't spank. However, you WILL raise a terror if you let the child control you and your home. As long as the child is safe, ignoring negative behavior works best at this age, as long as it is coupled with lots and lots of attention when he is acting appropriately.