Well, in theory I am against spanking, tough I am not a perfect person and I am a Latin woman with a temper, so I sometimes snap and slap. I would never administer a cold-blooded body punishment though.
I think though that as a parent, you have to, once in a while and not often, administer a real punishment. If you never do so, child might conclude that threats of 'getting the consequences of their actions' are empty, and I believe that it is ultimately a disservice to children not to teach them that the actions they undertake DO have consequences - it is a kind of vaccination, if you parents don't get the notion of responsibility across, life will, and in a much harsher way.
As soon as he had been grown up enough, in the cases when my son made a mistake, I gave her the option between getting punished or fixing the mistake by himself, with my help if needed - and he always chooses the second option now.
One anecdote : my father spanked once and only once in all my childhood. I was 6, and learning to ride a bicycle, and I fell down. My father dryly gave me a slap on the cheek and told me "Get back on" - I remember, I was so astonished by the slap that I got back on the bike and never fell down since ! That was the only time that my father ever hit me, and it worked a treat ...
I believe it is only hitting a child repeatedly and often that may arise fear and negative feelings. Besides, children have to learn to live with people who are not perfect, so if you really love them and thus they understand that you mean well even if you don't express it always the perfect way, they get along fine.