I agree with the majority of the posters; get some sort of self defense training. Find the one suited to your temperament and abilities. I like Ironraven's suggestion about the stick/knife training. I would add staff (just a really long stick) training to that. The techniques are basically the same. I also agree with the point about getting some close-in training. But, I think the best thing to remember is what my sensei said: "the best fight is the one that never happens". He always recommended running away; use and improve your situational awareness. Do not walk, look, or act like a victim. If you have to fight, make the other guy cry for mommy!

Now, a lot of this easy for me because I am 6'1", 235lbs and I have had very good training. I am not a typical target. My preference is to run. If not, then get in close and make life very miserable for the guy. I'm not a kicking guy. Knees, a la muay thai, yes.

My $.02

YMMV