And just in case you were looking for a legitimate response to the question, I vote the egg.
My reasoning follows simple evolutionary theory: At some point, something that was not quite a snake hatched out a mutated offspring that was, officially, a snake. That little mutant baby did well, and before you know it he was fathering (or mothering, I'm not sexist with my theoretical mutant snake babies) all over the place.
The first snake obviously survived better than that freaky snake with the one leg. Otherwise we'd all be breeding the fantastic Peg-Legged Pythons.