You absolutely must check out Pike Place Market and grab a cup of coffee at the original Starbucks - the "geek" standard for myself - go sit down in Starbucks and pound out some code.
If you're interested, you should for sure go see the Boeing Factory and the Museum of Flight.
The Emerald city is almost always rainy, but check the weather beforehand because if it's not going rain, the weather will be amazing.
Good restaurants would be The Cheesecake Factory, which isn't Seattle exclusive, but it's still good. Anthony's Restaurant is an amazing seafood place with a good drink selection - (Wild salmon is outstanding).
If your in the mood for a snack go to Dick's drive in which has awesome burgers and shakes - Seattle exclusive and a hidden gem for tourists if you ask me.
I don't spend a ton of time in the city, but when I go there I always have a great time. If you have any questions let me know and I'll try to answer them.
Thanks for the clarification.