I'm nowhere close to being a baseball historian, but the Ichiro-era in Seattle was great, personally. After Griffey left, we were blessed with another athletic freak of nature. He came, and the 116 game season followed. Sadly we didn't win it all, plus that was Ichiro's only postseason appearance.
As for my fellow Seattlites/Ichiro-lovers, I think Ichiro has earned himself the Steve Nash Corollary (its the most current name I can think of for it). Like Nash, Ichiro stayed with a team for much longer than he probably should have. Stuck with it through thick and thin. Reports I'm reading say that he requested a trade, so he gave himself an opportunity to play for a contender -- Nash goes to the Lakers, Ichiro being traded to the Yankees -- after dedicated much of his prime to a team. He earned himself a chance to win a ring.
I don't cheer for the Yankees, cause its the Yankees, but I'll cheer for Ichiro. I'll miss him in the Mariner blue.