Bell Bellistic full face at Jensen for $34
Just picked one of these up in blue.
Fit is right on, (medium), and with the first time buyer coupon, shipping is free. 930 grams on my cheap scale. Has a clip chinstrap for easy on and off, and wore it with sunglasses for 4 hours last week with no issues.
It has 13, not 15 vents, but there are 2 more vents the top that are not cut out of the shell, so as soon as I get around to it, i'll cut those out.
Bell Bellistic Helmet '08 > Apparel > Helmets | Jenson USA Online Bike Shop