Football - Seattle Seahawks (one Super Bowl appearance)
Baseball - Seattle Mariners (no World Series appearances)
Basketball - Seattle Sonics (1979-80 World Champs, Sold by Starbucks to Oklahoma City)

Over 100 years of organized sport and 1 Championship from a team that no longer exists. Guess I could've mentioned the Seattle Metropolitans 1917 Stanley Cup Champs. Recently saw Seattle was named the "Worst Sports City" due to their teams ineptitude. We would like to see a championship.