What you wear all depends on the level of risk you are personally comfortable with taking. It's not a fashion show or a test of bravery. Motorcycling is already a more dangerous mode of transportation than a cage but we've all decided that's a risk we'll take.
I wear jeans most of the time (have one pair of leather pants but rarely wear them). In the summer, for commuting I wear a T-shirt only, for touring I usually throw on a jean jacket or a leather jacket to stop the sun from beating down on me. I got a DOT Beanie for the cruiser and a 3/4 with shield for the Duc and inclement weather. I also have a rain-proof touring jacket with removable lining for winter and rain and pull-over rain pants. But I always where good leather boots (Chipiwa (sp?)) and good leather gloves.
I would ride without a helmet if it were legal here. In fact, the beanie is illegal in Japan ... over 400cc and your ears have to be covered by the helmet, but I haven't been stopped yet.
I like feeling the wind on my face and arms (I understand why dogs stick their heads out of windows in cars).... it makes me feel more in tune with the environment and the bike ... with a full-face I feel safer if I get hit, but I feel like I have less chance of avoiding being hit due to being more distant to my environment.
Well ... that rambled on a bit, eh ... remember this is just my opinion and your milage may very.
Ride safe and ride often everyone