Common words have more competition and uncommon words have a shot at #1.

Last year, I put up a site for a woman using "firstname-lastname.com". Her first name was very common, but her last name was very very unique, and she appearred #1 in Google instantly.

My first and last name are much more common and I can only get as close as the 2-5th page.

If I do a site for john-smith.com, that may never show up.

In your case, just because you get a domain that may be great like cars.com, do you think your going to out perform ford or chevrolet in the search results? Nope, aint going to happen.