The first game I ever played was Mario on the NES, but the first game I ever beat was Legend of Zelda on the NES. These two games were formative for me, and continue to influence the kinds of games I enjoy- platformers, dungeon crawlers, action-adventure games.
But Okami is my favorite of all time. Sure, it's not that original. However, Clover (now Platinum Games) took Ocarina of Time's core gameplay- Exploration + Tool based puzzle solving, and really made it their own while improving on, in my opinion, Ocarina's biggest flaw- it's combat. It helps that I loved the art direction, the humor, the Heroine, all of it.
It's not like my love stops there though. I'm still a huge Legend of Zelda fan, and I'd say that Castlevania: Symphony of the Night and all of it's spawn have replaced those idyllic Mario platformer games. I'm always on the lookout for the new and different.