I use a Giro Transfer http://www.amazon.com/Giro-Transfer-.../dp/B000BO3D18

Last week I helped my friend with a new bike and there were some very cool "reflectorized" helmets by Specialized. I am considering one of those as my next helmet.

Any idea how often un-crashed helmets need to be replaced? I remember reading somewhere that it was 3 years. I got mine in 2009.