So, in the past I have always insisted that Revit is a complete solution without any need to use other programs, boy was I wrong!!!
Since they have opened the Software Development, I have seen the value in numerous add-ons, as mentioned previoulsy.
One new add-on I have been playing with more recently is Artlantis. They have released a direct export of your Revit model to Artlantis, which is a really fast compact program to provide you with an effective render solution.
You can downlaod the plugin from their website, by clicking HERE
After loading the model into Artlantis Render, by not even looking at a help button, I applied materials and produced this render.
Adding materials, I spent about 3 minutes, and the render took 4 minutes.