Rubbermaid for all the reasons already stated PLUS, since snakes generaly do not like huge cavernous enclosures that make them feel unsafe, you can give your snake a cage just right for him, and when he outgrows it you dont mind getting a larger one for 10-15 bucks!

Both my rubbermaid enclosures keep a humidity level of 60-67% with simply a water dish inside. 8)