By far Calumma parsonii. Other ones that were extremely neat to work with are K. matschiei (Giant Fischers), T.deremensis, T. quadricornis and T.melleri. For smaller chameleons Trioceros montium and want to work with Bradypodion species in the future.
It is kind of tough to label best chameleon as I'm for the most part a fan of them all.