bottom line is... EVERYTHING you wear has to be breathable... and if it's not, then you have to make opportunities to get rid of excess moisture...
But then there is the concept of the Vapor Barrier. The article does and I certainly agree about the waterproof jacket on the outside of bike clothes will be drenched in no time is basically a vapor barrier further from the skin, but the concept of a vapor barrier as close to the skin is contrary to the breathable aspect.
I haven't tried it yet, but there are a bunch of backpackers and hikers who swear by it.
Article on vapor barrier
Jay