I'm looking for any tips for BP/snake specific photography.

I'm trying to improve my Ball Python photography. I'm currently using a Nikon D80 with the standard 18-55mm. I'm struggling with keeping the entire depth of the Ball Pythons in focus and keeping the lighting even.

Specific questions are what lenses do you use for shooting your BP's and other reptiles? I've heard a few people swear by macro lenses for BP's. If you use a Macro lens do you use one in the 50–60 mm range, 90–105 mm range, or the 150–200 mm range?
And for you macro users do you use a ring flash at all? I've heard they help keep you light nicely even at close range. I saw an affordable ring flash over at Amazon http://www.amazon.com/Macro-Flash-LE...8736644&sr=8-1 Anyone have any experience with this model?