I believe you would need a model release for this as you can clearly see the girl. Not trying to start anything, I actually hope I'm wrong as I feel it's a public place not private like there home. Candid shots like these are great and I feel you did a terrific job on it. So, if anyone know for sure let me know.
Actually, it's a moot point because this was a planned shoot... the model hired me for her portfolio, this is just one picture I took during the shoot. She knew I was there.
HOWEVER, let's assume I didn't. The law gives me the freedom to capture anyone in public view, so I wouldn't have broken any laws by taking the pictures. Also, I wasn't inside the coffee shop, I was outside, so the coffee shop couldn't even prevent me from shooting because the large window is clearly designed to be publicaly visible. If someone is sitting there, anyone can legally take their picture. Yet, the act of taking a picture, and the act displaying/selling it are separate.
The usage for this picture would most likely be protected as a work of art. The only time I would need a model release would be if I used this work in a commercial setting... meaning I used it as a commercial for, say, a coffeehouse or brand, without telling the "model."
The law is a bit more gray about displaying it on my website... It could be described as advertising my business, but unless I used it for a specific ad campaign, it would be hard to say that I used it commercially.
All of this is my understanding of the law here in the US.