Originally Posted by arg

Tough call, either way you'd lose traffic to people thinking it's skull.com. I'd consider buying skull.org, and register both theskull.com and theskull.org, then establish "theskull.org" as the primary site, so people mis-remembering it will be more apt to misremember it as "theskull.com" or "skull.org," which would redirect back to theskull.org.