I have also heard good things about the Arai. Has anyone tried the Airoh S4? Looks almost like a copy of the Arai, but for half the price.

Airoh Helmet
 

I just bought the Airoh S4 (matte black) and I'm very happy with it. You can remove the peak and the visor but in order to do that you have to remove two screws, not difficult but also not as simple. When you flip up the visor it doesn’t get all the way up, so at the beginning was a little annoying especially if you try to fit some goggles. On the nice side, it is very well priced (around $220), extremely light and quiet.
Since basically I only ride pavement to get to the dirt, I use a no peak with visor only configuration, and then switch to peak, no visor & goggles. Works out beautifully.