Nadine - there's a great book "Raising a happy child" (see the link in my signature) that deals with this kind of stuff.

It's written from the point of view of a parents group, with experience of different parents about what does (and doesn't) work.

And yes, the odd smack is OK, but to lead up to that is a great thing IMO, so well done on you for that.

Oh, and supernanny smookernanny. How much of that show is edited out, I mean really!