For me, it was OoT, and I played once at my cousin's house, but I didn't like it. Then my aunt got Majora's Mask, and I played that for an hour, but I didn't like it much either (though it would eventually be one of my favourites...). Then Wind Waker came out, my brother bought it, and he played it all day and night, with me just sitting there watching him. That was the first Zelda game I really enjoyed playing.