Last time my family and I went to Seattle we took the Duck tour and visited Chihuly exhibit in the Seattle center. I liked them both! Anyway, you only have three days - there is plenty to see. Just dress up for a drizzling rain and laugh at all these complaining locals - you don't have to survive there for months at a time ;-).
If you'll get a car, another attraction in Seattle area that I like is Snoqualmie falls. We used to go there a few times when we lived in Bellevue. Depending on weather, it could be quite beautiful.
Oh, and there is a thread on apug about Ted Gangler's exhibition of color carbon prints in November. If you can see it, you're in for a real treat!