Helmet choices?

So I was looking in to some protection. I don't want to make myself a huge target, but head protection would be a priority. I have an M-1 Steel Pot Helmet from WWII, a PASGT Kevlar helmet from desert storm, and will be getting an M-18 Swiss Steelhelm. These, a long with a few construction helmets and motorcycle helmets, are my options at the moment. What do you guys think? Which should be used, if any?