Mark Carey, I get that you believe a small prime like a 35 or 50mm is ideal for street shooting because they're lightweight and unobtrusive, but I (perhaps wrongly) infer from your posts and excellent blog that you feel using a long lens is somewhat akin to cheating. Certainly, we each have our own styles, and your galleries are truly admirable, but I'd like to offer up an additional point of view.
Like you, I believe in remaining as discreet as possible, melting into the background and letting the candid drama unfold around me. And while I agree that longer lenses are more intrusive as no one likes having a "big gun" aimed at them, they are often the only tool that allows you adequate distance to permit certain events to unfold unabated. When you can get up close, wide, bright lenses are awesome, but when you can't (or shouldn't), long lenses afford their own special anonymity.
For instance, while riding my motorcycle across Ecuador I stumbled upon a funeral procession (they were on foot). It was a sad day, to be sure, as a small baby had lost his/her life. But the glimpse this allowed into the lives of these mountain folk was truly engaging. There was no ethical opportunity to stop and pull my DSLR and wide angle lens out from my tankbag, so I was inclined to motor ahead, find a discreet place to pull over, and use my 70-300 lens to capture the scene without disturbing the procession or offending the distraught.
I can think of many other examples, but my point is that street shooting, like every other type of photography, requires a great deal of flexibility. And while carrying a longer lens adds weight and bulk to your kit, it's sometimes the only way to seize a moment.