Haley's Corner Bakery (Kent, WA): I purchase gluten-free bread from Kress in downtown Seattle. The basic loaf is $7.99 but it's the same size as a regular loaf of bread. When I make sandwiches, I place two slices in the microwave for 30 seconds.
Flying Apron - Gluten-Free, Organic and Vegan Baked Goods (Fremont). I haven't tried their goods yet but everything on their website looks pretty yummy.
Sweetcakes (Kirkland, WA): Another spot I'd like to visit.
Grainery (Burien, WA): Ingredients in bulk. I can't remember if xanthan gum is available in bulk. The next time I'm there, I'll make a note of it.