Selecting a domain name sounds like it would be an easy thing to do, but with every day that passes the number of domains under registration increases and you will find that even names that seem unlikely to be taken in fact are already used or squatted on.  Squatting on domain names was a huge and very profitable industry for years, especially during the dotcom boom of the tech industry, but in the last years some legislation and court decisions have decreased this practice, but not eliminated it.  We will talk about the factors of getting a "good" domain name in later posts.

If your name is famous and someone else is using that name as a domain name then you may have a case to sieze the name to prevent abuse.  If you register a domain with the letters ebay anywhere in the name you can expect to get a scary letter form Ebay about how you are forbidden from using that domain.  Ultimately you can do whatever you want, but it behooves you to know the possible consequences.  While a company like Ebay cannot bar you from using a domain name that contains their name in it, they are also equally free to sue you over it.  If your name is Susan Debayer then you certainly have a clear right to own SusanDebayer.com, but that doesn't mean the legal machine won't send you a nastygram anyways.  (by the way I don't know anyone with that name and just made it up to fit my example, my apologies if I picked your name out of thin air)

Stick to names that are defensible by you or your organization.  If you pick a domain name that leverages someone else's reputation (even by a misspelling of that name) then be prepared for someone to come after you which will likely take both the fun and the profit out of the entire endeavor.