How important domain name for SEO

Is it important to have a domain name  for your website that contains the keyword(s)?

For instance, http://www.dentistparnters.net for a keyword search “dentist partners”.  This website was ranked #1 on the keyword “dentist partners” within about 2 months.

I think Google does consider this as positive factor. Depending on a level of competition the domain name relevance to search keywords may play significant role in a website ranking. The higher competition the less credits your website gets for the domain name relevance.

On my experience the relevant domain names get positioned well and relatively fast on low competition keywords.