I have many favorite Ocarina songs, but here is the list of the ones I like, in no particular order.
Bolero of Fire: I like how the simplicity of this melody reflects the Death Mountain crater. The drums are cool, too.
New Wave Bossa Nova: It's such a nice song and really fits in the with the type of music the Indigo-Gos play.
Nocturne of Shadow: It's eerie, but tastefully eerie. it really suits the Shadow Temple.
Saria's Song: So mischievous and playful! Also, how can forget Darunia dancing to its beat?
Serenade of Water: This one is so elegance and peaceful. I can imagine swimming with this music in the background.
Song of Healing: This song is emotional in ways I can't explain. It's the type of song that is soothing, but in a different way from the Serenade of Water
Song of Storms: Catchy tune that actually truly reflects the going around of the windmill, as Guru-Guru puts it.
Song of Time: Pivitol of both games in appeared in, it is one of the most iconic of all the ocarina songs. I love how the lower notes sound as well