Theo Valich from TG Daily had an interview with Intel's ray-tracing expert Daniel Pohl. Here's a snip from the article:
TG Daily: There seems to be a lot of talk about ray-tracing in the media and all of the advantages it can bring. Is Ray-tracing the holy grail of rendering?
Daniel Pohl: Personally, I've been researching real-time ray-tracing for games since 2004. Back then on Quake 3: Ray Traced (www.q3rt.de). I figured out quite fast that there are a lot of benefits in using that technology. For example, for reflections and refractions you are simulating rays exactly like in nature. You get high quality results in an easy way. Looking several years ahead, I can't imagine that game developers still want to use the approximation for those effect that are currently used.
In general, the usability of ray-tracing for games depends also on what speed-ups we can expect from researching faster algorithms and how hardware will evolve.