I don't have a local bar in Oregon yet, but my favorite thing about my preferred spot back in Lake Placid was having my usual order waiting for me on the bar once I walked in.
Darrell's in Corvallis is a good dive bar/restaurant, and so is The Peacock in Corvallis. Both with colorful clientele and quite a history.
No article about Oregon Dive Bars would be complete without those two. Also, the Dixie out in Tangent, Oregon has a colorful clientele, and quite a history!
Just my two cents, for what it is worth!
Wishing Well _St.John's, Portland, Oregon. 7/8 gritty local flavor (among other adjectives), 1/8 those who come to people watch and soak in the irony (and get 'effed up on the numerous "greg" drinks, "Gregtini, Gregarita, Grega colada". Closest thing to a modern day Hunter Thompson experience in PDX.