Best Mid-Sized Snake?

I've got three carpets in tubs and 2 in cages. They all do equally fine, personally I'd rather have them in cages just because it gives them some climbing room but I don't think it's that big of a deal to the snake.

Blood!!!!! :D
I adore bloods. But, that's just my opinion. Their colors and patterns are gorgeous and they are very wide (=impressive to handle) while males rarely exceed 6ft, though females are larger. They do have a nasty reputation, but, from what I've read, a CBB hatchling that is handled regularly will quiet down nicely.

Oh, and bloods do best in tubs because of their humidity needs. Definitely not arboreal snakes.

my boa was way over 9ft... only bit me twice, once when he was about 3ft and again at about 6-7ft.. the later hurt pretty good lol.

boa is an awesome snake, tho i cant see it being a good tub snake! really need a good size enclosure!