Fabric Depot, the waterfall tour along the Columbia River Gorge, Mt St Helens (its amazing to see the trees still blown over and all the regrowth), the Olympic Penninsula (my favorite place before the Twilight madness was LaPush (Second Beach has the best tidepools ever) and I loved Cape Flannery, Pikes Place Market, the Newport Aquarium, the Japanese Gardens in Portland....
how long do you have???