Try to get up to Newport and see the aquarium there. The beaches there are nice as well, as are Lincoln City and Cannon Beach, but that's quite a bit north. If you do go up that far, check out Ecola State Park. Great views, some really clear examples of erosion and the power of weather, and it may look familiar if you watch movies.
If you can get to Tillamook, visit the Cheese Factory. There is a reason they have won awards. They also have cheeses there that you won't generally find in stores. They had a white cheddar garlic the last time I was there, and while it might sound a little odd, it was fantastic. It was great on burgers and the garlic was a really complimentary taste, not overwhelming.