jedito wrote a review of Giro Flak Helmet on July 29, 2010
Sure, it's not the lightest helmet in the world, but it breathes fairly well for this style of helmet and looks decent enough.
Also, it's tough as hell. It's a real skate style helmet, so the plastic shell on the helmet keeps it usable if it's dropped or if you're involved in a minor spill. (Skate style-d helmets that are just a foam shell will crack and break fairly easily, just like road helmets, making them useless after one impact) Sure, it adds some extra weight, but you aren't likely to have to buy a new helmet anytime soon.
Most importantly, if you're in a serious accident, it'll keep your brains on the right side of your skull. I got door-ed going pretty much full tilt (in a bike lane!) a few weeks back and went down HARD. The Flak did it's job well, and it has the busted foam and skid marks to show it. I'm 100% it kept me out of the ER that night. Outside of some roadrash and a busted up leg I came out of the accident ok, especially relative to how hard I hit the pavement.
A buddy of mine had a similar accident and damn near ripped his ear off while sliding on the pavement. With the Flak watching out for me my face was... Well, no worse than it was before I went down.
I'm buying a new one to replace it's fallen brother, that's about the best recommendation I can give.