We used a laminated cork floor over our radiant floor in the bathroom--mostly to prove that it could be done. The very thin layer of cork is warm to the foot in all weather, quiet and resilient even in a 1/4 layer.
We love them.
For more information:
Read "Can you offer tips for comparing the indoor air quality effects of different cork flooring products?" a Q&A answered by Peter Kellner.
Also, check "Is cork flooring really a green product? It seems fairly accepted that it's a renewable raw material, but is the final product really green?" answered by David Bergman.