I am looking to purchase my first bike helmet. I have done some online research (before going into my LBS) and the Bell or Giro lines look like good choices. Either one better? Other recommendations? I really would like something that offers tremendous ventilation, as I overheat and sweat terribly. And biking in NYC in the summer is brutal, especially when you are inbetween buses, trucks, cars, all blasting you with heat. Also, are visors really that helpful? I am willing to pay up to $100.