Geographical - your choice of the magpie is better than what my dad and I used to associate with "Eastern" Washington (Sequim residents way back then): rattlesnakes. I inherited my dad's respect (okay, fear) of snakes. And for what it is worth, dad used to come to "Eastern" WA to hunt deer in the Methow River Valley...... Eastern? ;-)If we are going biological, I use the beautiful Black-billed Magpies as the line of the Cascade crest. I wish we had Magpies on the westside. Seeing one of those magnificent birds is always a great thing.
I agree with some here, Central WA has it's own geographic coolness and I like that, not West versus East.
Where in this state is there not geographic coolness? Yes, I love what the ice age floods have done to the landscape in the Basin and how those same flood events allow us to see the transition from granite to basalt as you drive along Banks Lake but I also loved growing up on the OP in the shadow of the Olympics and having the Dungeness River a stones throw away. Dungeness Spit, Ediz Hook, the glacial till of the Elwha.......
Last time I checked, this is still just Washington State.