I'm sure that the people recommended above are great. That said, I'd go with Aaron Reimer. He is an outstanding caster, and more importantly, an outstanding instructor. On top of that, his contribution to Spey casters throughout Pugetropolis is huge. He is out on the Snoq something like 49 Saturdays a year with his rods and lines giving free clinics and instruction. Sure, he'd be happy to sell you rods/reels/lines, but it isn't a 3 hour sales pitch. I've seen him spend a very generous amount of time with guys he probably knows can't buy anything at that time. The vibe I get from Aaron is that he's doing because he loves it, and because he loves to share what he knows. To me, that's the textbook definition of someone who deserves business.
I will second the mention of Aaron Reimer here. he has given unstintingly to this sport, an invested countless amounts of energy, care and money into creating a welcoming culture around his Saturdays on the River. You will find some of the best rods, lines and instruction available there. Just damned good people.
I am taking lessons from Aaron right now. We meet at a couple of spots on the Snoqualmie River. His 12 hour lesson package can't be beat; and besides the casting instruction, the amount of fishing information he provides is amazing. Very strongly recommend him.