When I briefly lived in Seattle, I loved to work in the coffee shops there. They were idea with lots of tables, great wifi, and tons of power ports. They came in two varieties:
So quiet that you can hear yourself think
So loud that everything turns into white noise
Since moving home to San Francisco, I've found the coffee shops to be quite lacking as a place to work.. Probably by design since the cost of business here is twice that of Seattle for cafes. So I work on my balcony when the weather is beautiful. Sometimes I'll take my laptop to the Atrium in the new mall on Market St., or to one of the hacker or shared worker spaces. I like having other people around who aren't trying to talk to me when I work.
However, since purchasing a very comfortable Kinesis keyboard and a 24" monitor, I'm finding it harder and harder to work on my 13.3" laptop.