In Eastern Oregon check out Hell's Canyon. In the rest of the state check out this scenery http://hipforums.com/forums/showthread.php?t=6939
I lived in Oregon for years, and grew up all over the Pacific Northwest. It's wonderful. Eastern Oregon is REALLY BIG, so it's hard to just list off the great sights, you know? It sounds like you're already planning on spending a chunk of time in and around the Willamette Valley, and EO's a pretty good haul from there (fair warning for a short trip!). Eugene is a great town but tends to be too cool for school. It's full of what I call "snobby hippies" and "hippie-crites". I get fed up with it quick. Portland has a lot to offer, also... For these reasons, I found myself spending a lot of time (home-wise) in Salem - it's an hour to Portland, Eugene, Mountains, and beach. Right in the middle, who could ask for more? Of course, Salem itself leaves something to be wanted, but there ARE some cool people. Portland and Eugene both have drum circles usually near the Sat. Market (in Portland it's on the waterfront, in Eugene it was always by the courthouse) Salem has a circle Wednesday nights I beleive, at their waterfront. GO TO SILVER CREEK FALLS FOR A DAY. It can only be described as a religious experience, it's like it's own little rainforest. Beautiful. (Oh yeah, and jump your ass in that cold Pacific for me, too!) As far as Eastern Oregon goes, like I said, it's BIG. One of my favorite places is more "central oregon" - Crooked River, near Prineville. Beautiful country, Oregon's high desert. Do you have a more specific area that you're thinking about? EO has a very different vibe from WO - more of that cowboy thing going on. The coolest thing about Oregon, is it's one of the few states that really has EVERYTHING to offer. Mountains, beach, desert, forest, cool people and closed-minded people. Awesome. I'm going to stop going on now, but if you need any more info, say the word and feel free to PM me!