I don't think that you can go wrong by choosing Spokane. The city itself is just big enough to have most of the amenities of a big city, yet it is small enough to have almost a small town feel.
As far as outdoor activities the selection is near endless. You will be very near to some of the most beautiful scenery in the country.
My favorite spots in the Spokane area would be the Pend Oreille County area. Pend Oreille County is sometimes known as "The Forgotten Corner" of the state, as it is very rugged, remote and beautiful.
Here is some more info on the Pend Orielle Area.
Pend Oreille Scenic Byway
International Selkirk Loop
North Pend Oreille Scenic Byway
You will also be very close to the wonders of Montana...