I'm on my third Giro Gila. Sadly, they don't seem to make that model anymore, but you can find them at Performance and Nashbar on clearance sale. I'm thinking the Havoc might be a good choice also.

My LBS told me that $70 to $100 is the best range of helmets. Above $100 you pay for more vents and better styling, below $70 you find the bargain basement stuff for weekend warriors.

I have a small head, and Giro is the only brand that fits me well. They definitely have better venting than Bells.