1) Airius http://www.amazon.com/Airius-Furius-...436232&sr=8-17
2) $30 - it was the cheapest helmet at the LBS that fit over my bun. (I have very thick hair that went down to my backside before I cut three inches off, so my bun is pretty significant)
3) A crash where it absorbs a good deal of impact, and/or finding one for under $50 that matches my bike. (Gawd I'm shallow.)