I used the shields on my first run through the game. Now I'm in the process of another run without shields, potions, Heart Pieces, Goddess Cubes, or any upgrades but Hero Mode isn't on.
I didn't like the harp at all...until I played Ballad of the Goddess. I couldn't beat that one side quest where you had to play the harp at The Lumpy Pumpkin.
There are a TON that I like but like you I'm going to give 5.
1. Wind Waker Theme
2. Hero of The Wind
3. Outset Island
4. Dragon Roost Island
5. Great Sea