Francois,
Note I have not lived in any of the areas, but have visted for pleasure/business to all three
My vote would be for Kirkwood. I lived up the road in Vancouver, BC for 10 years and if you don't mind the rain in the winter, it's pretty nice. Summers are outstanding. Never get's really hot. Cost of living is likley much less than the options in the Bay Area and Santa Monica, plus Canada, great beer and a cheaper dollar is only an hour away when you are living in Seattle.
If you like Alpine or Cross country skiing there are many options and the North West is one of the only areas in North America that you can get in some great skiing in the morning and then head out for a nice bike ride in the afternoon.
Fleck
Steve Fleck @stevefleck | Blog