Again, not trying to get into the OC/CC thing. Just pointing out that anything of high value exposed could make you a target. If that high value item is a gun, it also paints you as a "gun guy." My experience has been that "gun guys" get guns stolen much more often than those that fly under the radar.
For the most part I don't keep anything of value in my car. There's a 100 inverter I paid $20 for and a few cd's I've burned off. Looking in my vehicle you will see there's nothing in there.