When i lived there I thought The Guitar Store was a nice addition to town. Good selection of Boogie and G&L and good pedal selection. American Music Bellevue would have one Bogner, if you were lucky, but never a "selection". Good guys there though. Thunder Road in West Seattle had some decent used gear. Missed out on a nice '67 Fender Bassman from there that was a killer price because I was in the middle of moving and couldn't justify any superfluous expense. Guitarville used to be cool but I lost track of them when they moved several years ago. I visited them once in their new location and they had nothing of interest and it was far away enough where I didn't bother going back. Emerald City has some nice used gear but tends to be more high dollar, vintage stuff. They usually have a semi-decent selection of Dr Z. Northwest guitars in Bellevue carries Tom Anderson
I would visit these store but still scour GC's used sections mostly. Kirkland's, where I lived for the last year I was there was a wastleand and I gave up on it.