If you're near a University, check out their library. Most of the time they'll have a cafe, guest wifi, and a reasonable amount of white noise for a library.
Yep. I live a mile and a half away from a university and I use their library for working on side projects. I've found it to be a great place for helping me focus.
Years of schooling have programmed me to think that the library is where you go to be serious about getting work done, and I'm often more effective there than if I sit at my desk at home.
I've written to my local library organization suggesting cafe areas in some of the bigger libraries. Never heard back, but I really hope they think about it. It could raise some money and improve patronage. The local library is much more convenient for me than the coffee shop, but I need to be eating/drinking when I'm working on something.
I was surprised when I found that the library close to my place in London (at Swiss Cottage) has a cafe inside and seems to have a relax policy on eating snacks inside the library.