Domain names are very important for SEO when you try to build a niche website that will bring you money. All internet monetizers know that buying a domain that contains one or two keywords is better than having a subdomain with the same words.
When researching for domain names try to locate names with as many important keywords for you. If you don’t find your desired domain name, try using dashes.I think and from my experince, seperating the domain with dashesis good for serch engine optimization, for example the google bot tends to take the domain as it is and it will interpret it like www.computerp arts… using dashes is easyer for the bot to read.

So for customer friendly domains try to chose short names that can be memorated by people, easy to type and good for branding. For search engines and niche websites that help you make money try to chose long, keyword rich names that can be easy to find.

Oh, and for the domains you can chose from all the extensions because they are all treated the same by bots, especialy by the google bot, (content has a big influence for this), but if you don’t want to lose some traffic try tor register the dot com domain because people tend to memorize and type this extension first. Good luck with your domain hunting