Thought I'd put in my two cents about my trip to Seattle and my experience with conceal carrying. We went to all the standard tourist spots like the Pike St. Market, the Space Needle, the aquarium, the boat tour of the loading docks... Mostly no issue! And most all of the shops I saw didn't have any "no-carry" signs.
The only places I couldnt carry were the Space Needle and Safeco Field, but I wouldn't wanna carry there anyway since I don't have James Bond shot placement accuracy, although I'm getting close! :P
The space needle was the most interesting; they say they don't let you carry, and it is private property so they have it posted but you have to look REALLY hard to see the sign. But their security gaurds only checked my wife's purse. I went twice, and they never said anything to me. Didn't risk getting kicked out, and I generally respect property owners' wishes, so I left it in the car both times.
The aquarium is owned and run by the city, so even you open carry guys can walk around without issue. Just talk to the manager when one of the highschool girls working there bugs out.
Overall despite some news articles about people not being gun-friendly, I'd give Seattle a 7/10. Carry on!