How many days?
For us, Oregon coast is best enjoyed as a road trip with overnights, visiting different parts at a casual pace. We've only based ourself in 1 spot when family rents a large house.
Astoria is a solid northern suggestion, charming spot with great character. Manzanita we love for the views. For south (sand dunes, Natural Bridges, etc...) our favorite is
Silver Cypress near Nesika Beach. They have airstreams with hottubs overlooking the coast. Love that place. Don't miss Old Oregon Smoke House in Rockaway.
Again, there are so many places to explore, my suggestion would be a leisurely road trip. Stop everywhere. There is so much to see.