To register a domain name is the first step to set up your site. Here are a list of things you need to consider before domain name registration.

Does the registrar also host your website?
It is possible that you register a domain name with one company and host your site with another company. The only thing you need to do is to change your domain's DNS information.

However, it is not wise to do so. When there is some problem with your site, you may not be clear what problem is, domain name or hosting. The registrar and the hosting companies are very likely to just kick you around.

Did your consider search engine marketing?
Most people choose their company name as the domain name. This is understandable because they spend much money on marketing their company name and trademark.

For a startup or a small business website, it is wise to carefully consider the site content and relate its domain name with its core product or service. For example, if you are selling computer software, you can try to register a domain name that contains "computer" and "software". Some major search engines, such as Yahoo, put much weight on the domain name when they decide which site to rank first.