Along with the ocean drive... Evergreen Air/Space museum at McMinnville... The Gorge/Multnomah Falls...
I'll add these:
Silver Falls State Park - (You can view some of the water falls from the parking lots but to see all 10 you should hike it. The hike is steep with lots of stairs but if you are fit enough and have the time THIS is not a State Park you want to miss.)
Raft Trip out of Grants Pass
Astoria Column
Fishermen's Bend CG by Mill City - Best BLM campground in the nation (and yes, I consider it a "destination campground" because of the excellent program activities for the kids (geo-cache etc), the extensive walking/bike trails and the FRIENDLY secure feel of the park there are no less than five host couples and 3 BLM rangers there.