When choosing your domain name keep in mind what your domain name is going to be about.
Your domain name is like the title of your web site. So your domain name should be whatever you will be putting at the top of your web site.
Business Domains
If you are registering a domain name for a business you should obviously try registering the name of the company.
You may also try to register a name that describes your type of business.
Personal Domains
If you are registering a domain name for your own personal site or blog, you can try and register your first and last name.
The best domain names are short and sweet.
While you can register a domain name that is up to 67 characters long, shorter domain names are usually more desirable.
Make sure that it's a name that will stick.
Ask yourself, "If I told someone my email address at this domain name would they remember it?"