I'm a huge coffee shop fan. i love to work in them, because it makes even work, social. I spent a lot of time in Think Coffee, in NYC, this weekend. Great place and it has the added benefit of NYU students there. They bring a lot of energy and makes me feel like I'm back in Berkeley.
Think is one of my favorite cafe's ever. My two favorites in SF are the Grove and Apollo Coffee (my new, favorite place because of a friendly owner and good wifi).
What are your favorite places? Seriously.