For anything that gets close to what could be described as realistic lighting then an unbiased render engine combined with a decent machine will give great results with virtually no set up times (a point often overlooked by those that claim unbiased rendering is slower!).

From commercial offerings such as Maxwell Render http://www.maxwellrender.com/ to free unbiased renderers such as Indigo http://www.indigorenderer.com/index.php?option=com_frontpage&Itemid=1