I have worked with lot of species and have several on my top list, not a favorite per se but a list of possibilities. I like my beardies, and my frilled dragons, am especially fond of tokays but not many people agree with me on that one. One of the blue tongue skinks in the lab is my buddy but I prefer him over the other two blue tongues. He used to be nasty but after 7 years I think he has come to terms with the fact I am not going anywhere, He still has a go at others sometimes but I can carry him around like a beardie now. The other two skinks are nicer and therefore boring. I want a water monitor but don't have the space for one. I have also heard that komodos have good temperaments but I doubt that will ever happen.
I have taken care of turtles and tortoises before and am not real fond of them, and regardless of where you classify spiders they are still creepy.