Pick a name that fits your company and then a suitable domain, if your compnay works then buy the exact domain,
ie. XYZ domain XYZLLC.com or XYandZ.com and so on.
otherwise, you will lose the traffic that assumes xyz.com is your domain.
and not just from random visitors but important contacts like investors, who assumed we were at dropbox.com. even people who knew well that we were at getdropbox.com would routinely fire off emails to dropbox.com by accident.
the process sucks, but we're changing our name after wasting a lot of time hoping we could secure dropbox.com and going back and forth with the owner.