My personal favorite is elaphe climacophora--Japanese ratsnakes. They begin as brownish gray hatchlings, and become beautiful green and blue adults. They are a room temperature species kept pretty much like a corn, although mine love climbing branches as well.

Climacs tend to be more slender than corns, and reach 3.5-5'. Some people have found them to be quirky eaters, but mine rarely turn down a meal. Mine are also alert and personable.

I know I've posted this pic before, but it's one of my favorites. It's of my male as a hatchling. I'll try to post a pic of him as a two year-old in the near future.

rgds,
althea