I wear my Shoei RF-1000 for pretty much everything, and that's everyday. But in the summer heat I wanted an open face helmet just running errands around town. Something that I can put on quickly, without fiddling with my glasses. (My expensive designer glasses have very thin, flexible arms which are harder to push back in my RF-1000.)
BUT, I don't want to spend much money on this item that I don't seriously need.
How about a DOT/Snell Scorpion helmet for $50? That'll do it, even if a little ugly. I've seen worse, and at this price it's worth it for those quick errands.
http://www.bikebandit.com/product/19036Oh, yeah; it even comes with the face shield.
