To spank or not to spank?

Andrew has hit an interesting new stage which involves lots of whining, falling to the floor, and hitting when he doesn't get what he wants. He's a pretty strong 30+ pound 22-month-old, so some of the slaps he lands are painful. But, even if he wasn't strong, hitting is just unacceptable.

But how to get him to stop doing it? We speak to him in a firm voice and tell him that hitting is absolutely not allowed and put him in time out for a minute or so. But, that doesn't always work; he goes right back to the unacceptable behavior. So, I must admit that after some of his more deliberate and painful slaps to my face, I have tapped him on the hand or backside. And I really feel so horrible each time.

I really planned not to use hitting back as discipline, since I think that gets confusing for a child ("Why can mama hit but I can't?"), so I think I've got to give time out a bit more time to really work. I'm also going to take a friends advice and YouTube a few of the videos on hitting from his favorite shows ("Ni Hao Kai Lan," "Yo Gabba Gabba," etc.) and watch them each day for a while going forward.

Does/did your toddler hit and did you decide to spank or not to spank? What worked for you in curbing this behavior? I'm looking forward to your responses!