My favorite is
http://auntmarysquiltshop.com/ - it is in Smokey Point (now Arlington) Washington. I also like Gathering Fabrics in Woodinville -- in fact Western Washington has many, many wonderful quilt shops - each with its own personality.
Here is a site that is will give you a list of the amazing quilt shops that are part of the Western Washington Quilt Shop hop though it looks like you won't be able to see the shops until after June 1 :
http://www.washingtonquiltshophop.com/