Columbia River Gorge
Waterfalls, waterfalls, and more waterfalls! It's best to go to the most popular spots early before the tour buses arrive.
Astoria
A Lewis & Clark historical site, developed from the trading post established by John Jacob Astor. Check out the Astoria Column and the Columbia Maritime Museum (including the Columbia Lightship).
Cannon Beach
Lighthouses
There are plenty of lighthouses to visit in Oregon, the most well-known of which is probably Heceta Head. The walk to the lighthouse was pleasant and the volunteers staffing the grounds were very helpful. I scrambled around the hill behind the light trying to recreate one of the famous photographs but found it impossible to duplicate, unless I was prepared to break off many of the branches blocking the view of my lens. Other notable lights are Yaquina Head and Yaquina Bay; Cape Meares, and Tillamook Rock (visible from the Ecola State park).
Portland
There's something magical about being in large city and still being able to watch the alpenglow on nearby Mt. Hood.