Yep, pepper spray (mace) right on my bike stem (vertically) attached with a small ball-end bungee cord. I can grab it in an instant. I take it in inside with me if I go to a store, cafe, etc. (don't want some little kid grabbing it and spraying themselves and then sueing me!)

Also I take my cell phone handy, with 911, DH, and local police numbers entered into both voice dial AND speed dial.

I also tell DH where I am going on every ride.

Once when I was riding a secluded wooded country road, and pickup truck passed me, then pulled over to the side of the road and stopped up ahead of me. I turned around and went back the other way instead of going closer and riding past him. The next week a guy in town saw me getting on my bike and he said "Hey I was the guy in the pickup truck who pulled over to read a map and made you turn around and go the other way last week. When you did that I realized you must have been scared of me and I felt real bad, but I couldn't very well turn around and follow you to tell you not to be afraid of me- that would have been even worse! I'm sorry!"....it was too sweet.