My commute helmet is an inexspensive something or other, the brim is nice for rain/sun and I've got a white led flasher on the front and a red flasher on the back. My wife and kids refer to it as my "Dork" helmet.

I use a road helmet on my road bike. It's a little more aerodynamic (not that it matters, I'm slow) and just looks more appropriate for that type of riding.