On a recommendation, I took a particular teacher's beginner class at Hilltop Yarns a little over a year ago. I really valued her patience and clear way of explaining concepts. When I am ready for some more advanced techniques, I'll probably reserve an hour of her time for a one-on-one class. The other staff is also excellent -- very friendly and knowledgeable, and they make very good suggestions. I like the yarn offerings too, and was glad to see the shop phase out its needlepoint stock (since I don't give two straws about needlepoint! Make room for more yarn! Especially Rowan!). And I should also mention how beautiful the shop itself is (very).
Hilltop has a frequent buyer program, and your purchases are conveniently tracked on the store's computer for you. But I have to say that I think the fee is too high ($10, if I recall), and you have a year to purchase $250 in order to earn your $25 certificate, and once you get your certificate, it expires in 90 days. I'd rather take advantage of a frequent buyer program that didn't have so many strings attached -- like Acorn Street's, or even better, Seattle Yarn Gallery (punch card is free).