Wind Waker allowed for the most fun exploring on sea, while looking for treasures, fighting enemies and discovering different islands. You could always count on your King of Lions boat friend.
Wind Waker or Skyward Sword. Both for the same reason basically...exploring all the islands in the sky in Skyward Sword and the great sea in Wind Waker.
Definitely WindWaker. Even after winning the game, i'd go back to islands for fun pretending I owned them all xD I haven't played Skyward Sword yet either so idk how the exploration is in it.
I know a lot of people will hate me for this, but I still say that Phantom Hourglass' overworld was the most fun for me to explore because it felt like a mini Wind Waker in my portable device. I loved the sea exploration in PH as much as I did in WW.
I agree, Wind Waker was very fun to explore in. But I'm going to say TP is my favorite. There were just so many ways to find so many diffrent things. The only thing that annoyed me though was when all I usually go was purple ruppees and then reading''It won't fit in your wallet, though. Let's put it back for now."