Matt Cutts, of Google, answers the question "How would you explain the power of keyword domains to someone looking to make a decision on what kind of domain to go for?"

In summary, Matt suggests that a branded domain name may offer you some advantages. While keywords are great when searching for a particular product or service, it is the company name that you want your potential customers/users to remember. Amazon, Google, Twitter, Yahoo and Facebook are all branded entities with strong name recognition. While you may not become a household name immediately, developing your brand can become an asset for you.

Matt also hints that Google may be adjusting their search algorithm to favor branding over keywords.