I've lived in all three places, and vote Oregon.
If you were going to live in Boulder, CO, you'd get the same great weather (read, lots of sunshine), at a better bargain, in Bend, OR. And Bend is also an outdoors sports haven.
If you were going to live in California away from the coast, it will often be quite toasty and expensive. Living closer to the coast, to get the cool consistent training weather, will be expensive.
Portland and environs can be a little dreary to some, but I prefer to think of it as great training weather year-round. There's almost never a day when you can't go run outside. If Portland is too expensive, live across the river in the Vancouver, WA area (as I do). Commute, if necessary, to Portland for work and socializing, not to mention great mileage in Forest Park and on the Wildwood trail.
Also, don't forget that Oregon has no sales tax, while Washington has no income tax.