Japanese Gardens/Rose Gardens/Piddock Mansion/Washington Park
Columbia Gorge-Multnomah Falls, any of the falls, Beacon Rock, Bonneville Dam, Hood River Fruit Loop and Train Ride
Hawthorne District ( I love Fat Straw's vegan blended boba tea and there's a wonderful Korean restaurant-lots of great restaurants really)
NW 23 and the Pearl District
Newport Aquarium (Cafe Mundo in Newport is lovely)
Cannon Beach (sandcastle competition is fun)
Seaside - any beach really...
Bend has a whole host of good stuff within a couple hours too.
New Season's Markets are awesome
I'm trying to think of more...