I use plastic crock bowls meant for dogs that I can get at the dollar store. I have ceramic bowls in with my bigger snakes, but I'm thinking of switching them over to the plastic crocks as well. The ceramic ones are easier to clean, but they tend to be cool to the touch and I don't think I like that.

Are you using tubs or tanks? Do you have a heat lamp going? Holding any kind of humidity with a heat lamp and a screen top is a nightmare (if this is the case, try covering most of the lid with foil and switching to a ceramic heat emitter instead of a light).