Mine has changed four times. First my favorite was Ocarina of Time, it was the first Zelda I remember after all. Then it went to Oracles of Ages when I beat both it and Seasons. Then back to Ocarina of Time. Then after I had replayed Majora's Mask and was able to complete it 100%, it became...
I like both, but because dogs require more attention, I prefer cats. Plus I like the squeeks and chirps my cats make when they're looking out a window. I've never heard a dog make noises like it before.
I voted for 10. Although MM is one of my favorite Zelda games for the characters and the story (which was mostly due to all the intricate side quests), OoT had the best balance of story and dungeon crawling to me. I felt that 4 or even ~7 dungeons for MM and WW were too few.
Most played is AC: NL with over 1300 hours played. And second is probably .hack//QUARANTINE at over 700 hours. Maybe some MMOs have been longer, but I think solely online games are cheating a bit - it's easier to clock that many hours in when you are always having a different experience due to...