Since I'm not old enough for a CCW yet, I carry Sabre Spitfire pepper spray. Picked it up for $15 at Sportsman's Warehouse... I chose this one because the shape makes it less likely that it will spray my own hand if/when I ever need to use it.
http://www.sportsmanswarehouse.com/s...1260/cat100464
I also carry a nice sharp box cutter in my other pocket for good measure