I'm afraid the last two posts are incorrect. Key word domains did used to be very very helpful but not so much anymore. When google changed its penguin algorithm it greatly reduced the importance of domain names in an effort to combat SEO. In short if i buy beer.com i can put any content on it, maybe info about tables. then when a user searches beer they get info about tables, rendering google pretty ineffective. Concentrate on putting your keywords in titles, meta tags and content.
When thinking about your domain name, it wants to be short, memorable, catchy and always a .com
Hope this was helpful, Ben.