The Giro Chapter is a comfortable, lightweight and customizable. It's wonderfully shaped and includes an easy to use knob for changing the fit, shown below:
Out of the box it fit really well, and after a little tunning it's probably one of the most comfortable helmets I've worn.
I got the royal blue model, but there are several color options available. This helmets supports Giro's Tune-UPs system so you can put headphones into the hear flaps. There is also a closable vent at the top of the helmet so you can cool your head if you are getting too warm.
I think the only problem I had was that the very top of the ear flaps weren't tight against my head, and when skiing on the east coast with -30C weather, that tiny little gap lets in some cold air. A thin layer below the helmet helps alot if you are having this problem.