I've traveled quite a bit, and I really love the scenery in the northwest. I had to get up before dawn to make this trip, and driving through the mountains at dawn is really special. you can click on the picture for a bigger version.
There's a big line drawn through the center of Washington state; called the cascades, and the western side, where I live, is quite a bit wetter. Here I've crossed and entered the sagebrush desert that is eastern Washington. Eastern Washington is quite a bit sunnier, and the temperature varies more than in western Washington.
The geology is massive flows of lava that were scoured clean of dirt by gigantic floods and glaciers. The dirt that remains is relatively fertile, although it's pretty thin. It's excellent wheat and apple country. Recently I've seen more diversity in crops; grapes, hops, mint, forages of various sorts... more variety.
Here you can see the basalt on either side as the road cuts through the hills. if you look carefully at the horizon, right at the center of the photo, you can see mount adams, one of our active volcanoes, peeking up.