(L) [2013/05/14] [tby dbz] [Nvidia IRA demo] Wayback![LINK http://www.nvidia.com/coolstuff/demos#!/lifelike-human-face-rendering Digital Ira], really amazing photo realistic rendering demo from NVIDIA, it runs on my old gtx 470 too. Interesting that z-buffering with advanced shaders is capable of rendering photo realistic images just as well as (slow)random sampling based techniques, if not better(no noise).
(L) [2013/05/15] [tby davepermen] [Nvidia IRA demo] Wayback!never a problem as there's no environment interaction and stuff going on. the global part is where raytracing/pathtracing etc come into play.
put that head onto a body, into a real world, and ask for everything to be lit and shaded properly together, interacting and all.
this is in the end just cubemapping with a VERY advanced shader