If a pinlock is available for your helmet, definitely go for it. If not, I had pretty good luck with a universal stick-on from Fog-City. Of course you'll want to buy a second visor for your helmet, so you can take the Fog-City visor off in the spring, but it works pretty well at controlling visor fog. (Doesn't help with your glasses though.)
Love my Gerbing liner, and my First Gear gloves. Ride year round now, only stop for heavy precip, regardless of the temp.