(I'm going to give you a few pointers to breweries that I frequent because I know the brewers personally and am a fan of their beers).
+1 to Holy Mountain. Colin is brewing some phenomenal beer. Most of what he has on tap are various Saisons with varing strains of Brett. I think Holy Mountain is probably the best brewery in the state right now.
I agree with going to Ballard. Be sure to hit Lucky Envelope in Ballard, too. Fellow homebrewer-turned-pro Barry Chan's ENIAC IPA took Gold last year at the Washington Beer Awards. That is no small feat, believe me. From there, you are in walking distance to a bunch like Stoup Brewing. Fremont is not far, either. (BTW, there's a distillery about a block from Brouwer's, which is not a brewery, but is one of the best Belgian Beer Bars in the world).
There's another Nano called Outer Planet up on Capital Hill. It's a small brewery and Jim is putting out some great beer. He's one of the home brewers from my club that recently turned pro.
If you are on the East Side, there are a bunch of breweries founded by other members of my club that went pro. In Redmond, you have Postdoc (Tom Schmidlin's place), and HiFi (John, Joe, & Ryan), which is a block from Black Raven (not from my club), which is another phenomenal brewery. In Factoria/Newcastle is Resonate (Mike) Another cool thing about Resonate is that they are a pizza pub/brew pub. They ferment the dough for 3 days before it goes into the wood fired oven. It's simply awesome pizza, and the beer is great too.
HTH-