Honestly, I believe it depends on their age. I was brought up on the philosophy of "If you knew it was wrong and were fully capable of stopping it but didn't, you get spanked." It worked too. I tried to avoid doing the wrong thing. And then as I got older, I got spanked less, as it didn't effect me as much. It was at that point that taking away my Playstation 1 and or 2 and Nintendo 64 for a while was enough.
I don't believe what happened to me was abuse. I've done some things where I'm surprised I wasn't beat bloody honestly. I once did something so bad, it just made my parents and grandparents cry. They didn't touch me for it, not once. Though they didn't even NEED to. That's what I think it boils down to. "Does this child deserve a spanking?" If the answer is no, don't do it. If it's yes, do it. Just not excessively.
Anyone else notice a trend? As soon as spankings became a controversial subject, a whole generation of little shits who could get away with anything grow up thinking that still applies when they are adults. I like to call this group 80% of 4chan. (/x/ SEEMS to be okay at least.)