A difficult choice, but I'll say Seahawks' second Lombardi right now, this season, with the expectation -- thanks to the recent changes in ownership, GM, coach, and players -- that the Ms may have an even better shot at getting close to the World Series in 2017 or 2018.
That said, the first ultimate trophy for one's home team is the most special. So once the Ms win the World Series trophy, that will be more special from a single-event standpoint than will be the Seahawks' second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth Lombardi. However, once the Seahawks accomplish all the things "required" to make them unquestionably a bonafide dominating dynasty of historic proportions with RW getting as much, if not more, credit as any other factor, that would easily top the Ms winning any number of World Series trophies.
Don't forget how thunderous the packed Kingdome was, 12-15 years ago (whenever it was), when the Mariners were hosting playoff games. Those games were just as electric as any Seahawk playoff game! Would love to see that again, at Safeco Field.