If you have small children in the house, I'd definitely go with a ball. RTBs can exceed ten feet, meaning they are not exactly easy (or safe; a red tail could easily kill a child) to handle. Meanwhile, kids love BPs. I've got young brothers and cousins, all of whom love holding the BP. Don't get me wrong; RTBs are awesome pets, I'd kill to have one if I had the space, but maybe not the best choice for children.
As for choosing between the various balls, I'd go with the spider. Personally, I'm not a huge fan of pieds, and a het isn't nearly as nice as a morph. (Although I always argue that normals are my favorites.You really can't beat the gold on a normal.) Albinos are also awesome, but you may want a bit of extra cash around for feeders, caging, vet care, etc. Many people overlook the possible need for vet care and how expensive it is; I was one of those people. I got all of my animals from breeders, I didn't imagine I would have any issues. In the past three months, I have spent well over $500 on vet bills for my bearded dragon and ball python, which really put off my other plans.