i shoot street photos as well, i wait for the right light, angular, sharp, cutting light.. that yields the results i want.
what's the point of shooting in flat light? even when i feel like doing it, iso800 with f/5.6 usually gives a handholdable shutter speed around 1/60 seconds or so from my experience.
to be honest, i look at a lot of david solomon's street pictures:
http://www.flickr.com/photos/davidsolomons/
look at these:
http://www.flickr.com/photos/davidsolomons/4544868305/
iso1600, f/3.8, 1/25 seconds focal length 20mm: camera d300 (CROP FRAME)
is this a sharp photo?
http://www.flickr.com/photos/davidsolomons/4345250465/sizes/o/
probably taken on film. grainy too.
sharp and noise free?
http://www.flickr.com/photos/davidsolomons/708474465/
street = no flash?
http://www.flickr.com/photos/davidsolomons/187940918/
no noise?
http://www.flickr.com/photos/davidsolomons/186479008/
i wish people would stop making noise about noise. i've seen millions of noisy pictures that didn't bother me none, and millions more of sharp photos that were horrible.
there is nothing worse than a sharp photo of a fuzzy concept. ansel adams said that. perhaps he should added on that there is also nothing worse than a noise-free photo of a fuzzy concept as well so that we could quote him.