Seattle: Space Needle, Frasier and Starbucks.

Many come to Pike Place Market to visit the first Starbucks. Some discover that although it's known as the first Starbucks, the actual location was a block away but this was demolished and the coffee bean vendors (at the time, before they started to sell drinks) moved to this location, 1912 Pike St:

Starbucks numbers its stores. Interestingly, this store is number 301. There is no store number 1. The lowest number (according to this handy site) is 101 (also in Seattle). Who knows why!

A less-well-known but just as interesting (to Progressive Rock fans, at least) site in Seattle is Bass Northwest on Yesler Way. They have a fantastic mural on their wall, depicting the cover of King Crimson's classic 1969 album In the Court Of The Crimson King:

Also, having a store dedicated to bass guitars only - seems like something they'd do in Portland!