Spokane
Thought i'd add a bit. I have yet to get burnt out in the eastern washington area since it is so varied it could well take a lifetime to fully explore it all.
If you are looking for modern architecture or a jazzy new york street life this is not the place.
But if you primarily do landscapes, old bldgs,farms ,barns etc. its a good base to reach out from. And if you really want to do some architecture then Seattle is only 5hrs away and we have the latest. Many of the older towns around spokane can be quite interesting also in a Route 66 kind of way.