@dillyd Two definitely touristy things that are actually worth it, imo, are the Argosy harbor tour, which is about an hour long "cruise" that has lots of fun facts about the port/city, and the Underground (walking) Tour, with the last of the day being the "adult" version and all others being family-friendly. Pro-tip: If you want to hit a lot of attractions people mention, see if the CityPass is a good deal for you.
@dillyd my advice is to not do the space needle, weirdly enough it's the worst view in town because you can't see the space needle! You wanna go up the Smith Tower (historic) or the Columbia Tower (tall)
The best view of the city is from a ferry, they're like 10 bucks to walk on and go to Bainbridge or Bremerton and back, highly recommended.
@dillyd Of you're into boats, there are the locks in Ballard. If you're into sculpture there's the Olympic Sculpture Park. If you're into nice views and steampunk there's Gasworks Park. If you're visiting now there are a lot of cherry trees blooming; the ones at the UW quad were a gift from Japan. The rest of campus is nice too, especially their library. Speaking of libraries, the Central library downtown is nice too. 1/2
@dillyd Pioneer Square is historic and has lots of great bars and restaurants. The Chihuly glass garden/museum is a must. And of course Pike Place Market.
@dillyd assuming it's still next to the space needle, there's Chihuly Garden and Glass, a "museum in the Seattle Center showcasing the studio glass of Dale Chihuly".