I read a great blog post by Wayne Brockbank today on HBR about HR's focus on "talent" in the past years and why it is somewhat misguided. The core of the argument is this: organization is about making the whole greater than the sum of its parts, and not at all about maximizing individual performance. Searching for individual high performers, ranking staff according to individual performance etc is acting in accordance with a view of the world opposite to the idea that organization itself adds value. That the configuration of the parts, is valuable.
However, having a psychology background, I think that "who" you hire matters too - but maybe more to the degree that people bring ways of interacting with them into organizations. How people interact with each other, with systems and other artifacts et cetera, bring about certain patterns of order. This is what can give a company a competitive advantage. So, I agree with Brockbank that HR should focus more on what happens with talent once inside the organization. Maybe see themselves more as tinkerers of the "work system," and support for the organization to self-tinker, tweak and evaluate the effects of the tweaks.