I've got to agree with summer's sentiment that an upside down cross is cliche. Not only that, it reeks of desperation to appear anti conformist and rebellious. If you really wanted to piss Christians off you should get a crown of thorns tattooed around your head.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell