I think there are better ways to deal with problems with your child, but that sometimes what the child really needs is a little tap in the butt. I don't like when parents swat at their kids in anger, but a small tap in the butt (over clothes if in public) does not bother be at all. Or a tap on the hand if the child is touching something they should do. I think the problem is that too many people take it to the extreme or lash out in anger and that is where we get this "spanking is bad" mentality. I don't think spanking should ever be used in isolation. After the spanking, I think I parent should always speak with their child about why they were spanked and what they should do next time in order to avoid it.
As a kindergarten teacher, I see first hand the results of parents who do not discipline their children. People who's form of punishment for a 5 year old was a 5 minute time out (one minute per age of child)...even if it's the umpteenth time the child has had a time out for the same behaviour. People who were afraid of the "mental effects" of these time outs on their child (ie. if I sent a child to their chair in the middle of a lesson). People who are killing their kids with kindness. You cannot be afraid to be firm with children and show them who is boss. Most young children are not yet mature enough to moderate their own behaviour and need someone to moderate it for them and many will try to run the show if you let them. If you choose not to spank, that is your business. But a child needs to be disciplined, and I think punishment (of whatever reasonable form) is part of discipline.
One time, I was making a cake with a niece and nephew and he was really being a pip with her, but she was taking the bait. I told them a couple of times if they didn't behave the cake batter was going in the garbage. Well, they didn't listen. Know what? I did what I said - cake batter RIGHT INTO THE TRASH!! You don't get a good time and yummy cake if you don't listen and behave properly. And their hollering brought my brother running into the kitchen. I told him what happened and what I did and he sent them to their rooms as punishment. At least he backed me up.
I was sorry to waste the batter but I knew I had to.
My folks were tough but fair and for the most part - consistent in doing what they said they would. Many kids today are out of control because the parents don't have a firm grip on things (figuratively speaking) and the children are running the adults, sted other way around.