One site worth seeing is at Saltys on Alki beach at sunset http://www.saltys.com/seattle/, the foods ok kinda pricy but the veiw is amazing at sunset, you can drive to a park up above the restaurant and get some great shots of the skyline.
a drive around to Whidbey Island and Deception Pass and then back to Seattle by Ferry is a good day trip, plan the ferry ride for late afternoon the light will be better, that's if its not rainy... big IF, a trip to Mt Rainier would be great to.