It's very hard to tell currently because no one can tell the future. Base on previous situation, game manufacturer wants to make money, so they won't set an extreme high config like 2.0GHz above in order to cover as many market segment as possible, of course if you want extremely high quality you should have the top of the line rig but more than 80% of consumers don't even own such a high end system. So relax, even some latest games requirement is a 32MB video card and 1GHz CPU along with 128MB RAM.
It is morally wrong to allow suckers to keep their money
<A HREF="http://www.anandtech.com/mysystemrig.html?id=22996" target="_new">My System Rig</A>