Hi,
The other week a WIP was released with new material implementations of the Rhino basic materials. They should give you great materials to work with, sans the need to fiddle with settings a lot.
Plaster, Paint, Metal, Glass, Gem, Picture and Plastic each are implemented with optimized shaders behind the scene.
You can check the Gallery with the cycles tag to see what already has been created with the newest material implementations. And feel free to share your own creations tagged with cycles or raytraced as well 
Currently I know of two issues with materials:
- custom material not always working properly: RH-37339
- bump map on ground plane can show tiling effect: RH-37825
But other than those materials should be very useful.
Please do test, share your work and findings (including bug reports!)
Enjoy!