In Eugene: Falling Sky- lots of interesting, varied beers. Different takes on classics. Plus, an old school video arcade that is a bar across the street. While in Eugene, The Bier Stein is worth a visit for an extensive tap list.
In Corvallis: Block 15, and their beer restaurant The Caves next door. Well crafted beers, different styles like farmhouse and sours.
In Portland: Cascade Barrel House- generally a dozen world class sour beers on tap at any one time. Hair of the Dog- known for their strong bottle conditioned beers, but their brewpub has lots of beers on tap that are never bottled. Their mild is a great beer. Hopworks Urban Brewery- great example of NW and Oregon style beer, good pub food, and done with an organic and ecologically friendly bent. The Commons- homebrewer made it big going from nano brewery to a full on brewery with a tasting room. No food, but great, mostly Belgian style, beers. Breakside Brewpub in North Portland- better than their tasting room in Milwaukie and excellent food. A lot of their beers feature unusual, culinary, ingredients. Also, Deschutes brew pub in NW Portland is good, and features tons of one-off beers that will never be bottled and distributed nationally like their core line up.
In Hood River: Double Mountain- low key, casual vibe, great variety of beers including some sours and Belgian style beers with pizza. Pfriem- awesome BDSA, great brewery with a bias toward Belgian style beers. Logsdon and Solera are outside of Hood River and probably worth a visit if you have some time because they both make some interesting beers, including Saisons and sours. If Solera has Pretzel Logic on tap pay anything to get some of that amazing beer that tastes exactly like a pretzel.
In general, you can find great IPA anywhere in the Pacific NW. Boneyard ranks among the best, but there are also some great ones from Laurelwood and Ninkasi, among others.
While you are visiting, avoid McMennamin's brewpubs unless you are only going to see a restored historic building, their beer is mediocre, their food average, and their service sucks. Many a tourist has fallen for them and wished they hadn't when they check out other places.
I hope you enjoy your visit to Beervana. Cheers