Tim,
On the private side your best bets are: Alderra, TPC at Snoqualmie and Sahalee, all of which are pretty close to each other but about 20 miles from downtown Seattle.
On the public side things get murkier, there are no great public courses in the Seattle area, just some ok ones and you will have to drive a ways and then it depends on what you are interested in. For the CCFAD fan then NewCastle golf club is your best bet, great service, great views, high prices, excellent condition (actually plays fast and firm) and some good golf. Other courses with not so great conditioning are Washington National and Druids Glen, both cheaper, some better golf holes and without the CCFAD factor. There is a new Gary Panks course called Trilogy that is pretty cool also and is in very good shape.
After that you have to drive at least an hour to play anything decent.