If my city were more like amsterdam I'd be happy to forgo the helmet, but in hilly seattle between the chances of getting clipped by a suv or taking a tumble on a steep grade.. I'll stick with the helmet. I don't find it too much of an inconvenience. I just clip it to my bag after I lock up.
Fyi, Amsterdam is one of the worst places as a cyclist in The Netherlands. It's very crowded and narrow with very few separated bicycle lanes. The average bicycle infrastructure in the Dutch suburbs are way better.
