The moment your code begins to look like this

   -webkit-transform: rotate(-70deg);
   -moz-transform:    rotate(-70deg);
   -ms-transform:     rotate(-70deg);
   -o-transform:      rotate(-70deg);

you know that it's time to either drop the vendor prefix or to hope that there will not be another browser vendor implementing the exact same functionality and again protect it behind a prefix.

I know that technically, the transform specs are not finalized, but considering this kind of consensus (even IE seems to agree), would it even be wise to change the spec again?