If you want another ball python, then there are a ton to choose from.
If you're looking for another species altogether, I'd suggest a dumerils boa or one of the smaller locality BCI's.
I've heard lots of talk about dumerils boas... I'm going to have to research them. Are they known to be pretty friendly? I've also heard a lot about Rosy boas but I don't know much about them either. Yay, things to research!
Female Common Boa - Rosie
Female Terrazzo Corn - Mercury