I would think with paint or good seal the wood under wouldn't matter. I know certain woods are bad to use for reptiles though. Not for certain, but for safety reasons I would avoid Pine and Cedar. Don't quote me, I don't know for sure.
So I am currently building a cage out of 3/4" Oak plywood, and solid oak trim for the front. Using Spar Varnish to seal and silicone on the inside edges/corners for an even better seal. In case you don't know, Spar Varnish is used in Marine applications, so you know it handles moisture well :P. I put I piece of vinyl flooring on the bottom of the cage for even extra protection from moisture.
Heres my build thread if you want to check it out:
http://www.ssnakess.com/forums/gener...8-x24-x18.html
Keep in mind however if you do decide to use Spar Varnish; give it plenty of time to cure until you can't smell any fumes to make sure its safe for the inhabitants.