I've been mulling about a gun for a long time, but can't seem to work up the nerve for one. Its personally just too much power and responsibility. So I've been thinking of mounting a small to medium knife between the driver's seat and the center console by the seat belt.
I figure in an emergency situation I would be quicker and more proficient with a blade as things would likely be happening at a close range. Plus my right side would conceal it the draw as just unbuckling my belt. A gun would probably work better, but its a compromise I think could work.