a bairds rat snake. similar to a corn snake, but slightly more unusual. everyone has corns, bairds rats are easy to get hold of, easy to care for, tame as anything, and great fun - oh and they look stunning as well.
It's a close call between royals and corns for me, but I'll side with corns because of the feeding habits. As far as everything else goes, I think that they're along the same lines. I personally prefer to keep royals though.
i dont know what to say i put others too, because although corns are easy etc, they may just not be for you!!
BUT like others have said, if you do your reasearch, know what your getting into etc then why not any of those IMO