As far as whether a bike will get stolen, it really seems to depend on the neighborhood -- I know several bikes in my immediate area in Capitol Hill that just sit there (although I'm afraid that I just now jinxed them!). I bring my bikes inside, though.

Bike commuters, and people just biking in general, are pretty numerous and not unexpected. I can't seem to walk the block to the store without seeing somebody riding a bike. There are moments when I notice more bikes passing by my place than motor vehicles.