I've asked around a little bit whenever this topic comes up and the majority of people who I've talked to say that their best source of customers comes from people that they know.
Not a very satisfying answer for me, since I don't know a whole lot of people (maybe that's just my view of things, I could be wrong), and of those people, very few of them need someone with my skills and expertise (or, to be more frank, I doubt any of them would be able to match the paycheck I currently get from my employer). It's equally likely I'm not imaginative enough.
In any case, if anyone is "living the dream" in the Seattle area, drop me a line - I'd love to chat with you and maybe have a coffee (haha).