First of all, this thread is epic because Kabar posted in it.
I've camped plenty outside of towns on unused lands while travelling, and my first time technically sleeping on a city street, was in Berkeley, CA.
I started out by trying to sleep in the People's Park. Mistake. Cops found me about 2am and rousted me, ran my ID, let me go with a warning, said "suggest you find an alcove downtown". So I found an alcove downtown. It took a while because most of the good alcoves were already taken by that point.
The alcove I eventually found near Shattuck led to a barred gate to a courtyard. A vine had grown up all around it. I thought, "Great, some greenery, I'll sleep well here." Nope, the wind kept roaring through the alcove and some kind of compressor kept going off in the alcove every 15 minutes or so. I didn't sleep very well there.
By 4am or so I ended up packing my bedroll up and headed out to find another place to nap for an hour or two. Found an alcove on University and it was 1000% better just due to the lack of wind. No pissy smell either, unlike a lot of the other alcoves. Slept like a log, out by 6, no hassles.
Side note: A lot of the alcoves in Berkeley have "No Trespassing" signs, the ones that aren't are apparently fair game for sleepers. I'm not sure what would happen if you slept in one with the sign but there were plenty of cruisers that might take it upon themselves to enforce it. None bothered me after I left the park.