The one near me has no problem with someone setting up a laptop for a day, has plenty of plugs, never a line for the bathroom, and provides a quiet working space.
I live a few blocks away from the main library in my city, they have a fiber connection through the state college that's in our county, for 150mbs connection.
There are some people in there looking for jobs and surfing Facebook but there aren't a ton of people in there using the wireless.
The problem is, it's useless for anything but web surfing. No github, no apt-get, no ssh, heck I couldn't even download the latest Java SDK.
Public libraries, at least in the UK, has very strict policies on their broadband connections. zyou cannot connect to non-standard ports there. Normally only the 80 is open.
My local library has neither broadband nor toilet, but it does have power, and is always quiet. Crazygringo has described my days well, but I also have to coordinate my library time. There are paid workspaces nearby, which would cost about £150 per month more than the coffee shop, which I'll probably try out soon for a month. Working from home I certainly can't do in the morning at least, as I need the ritual of the 20 minute walk to "work". I believe Rene Magritte used to leave home in the morning, having kissed his wife goodbye, would walk around the block a few times, then return home to work.
Which ones? I sometimes work in the Swiss Cottage library and the Internet connection is usable and they don't seem to block ports. One alternative is to get a 3G/4G usb dongle.
The one near me has no problem with someone setting up a laptop for a day, has plenty of plugs, never a line for the bathroom, and provides a quiet working space.