Here's my Skyloft list ready to be scrutinized by you, the contestants!
The Legend of Zelda - Main Theme [Link is to the Brawl version, but I'm not necessarily referring to that particular version.]
If Great Bay and Bridge of Eldin are any indication, it seems the stage from the more recent Zelda title at the time of each Smash release gets the honor of having this very iconic tune from the series. A new and fully orchestrated version of the theme will feel right at home on this stage with its adventurous tone, something that fits well with the open sky and the prospect of exploring the world below.
The Legend of Zelda: Skyward Sword - Skyloft
Pretty obvious choice. Like how Delfino Plaza, Norfair or Green Hill Zone had their original themes, it makes sense for this stage to have its original music too.
The Legend of Zelda: Skyward Sword - Ballad of the Goddess
What could be called Skyward Sword's main theme. It also has been heard on this stage in one of the trailers, meaning it's confirmed.
The Legend of Zelda: Skyward Sword - Ghirahim Battle
An iconic tune from Skyward Sword. Intense sounding, the theme of the villain fits quite well with the gameplay. It also provides variety to the stage's music list too.
The Legend of Zelda: A Link to the Past - Kakariko Village
Skyloft is a peaceful town just like the recurring Kakariiko Village and this song is quite iconic as well, reappearing in several later titles including Ocarina of Time, Wind Waker, Four Swords Adventures and A Link Between Worlds.
The Legend of Zelda: A Link to the Past - Dark World
One of my favorite themes of the franchise. It sounds adventurous and grand, much like Zelda games themselves and also provides some contrast to the other songs on this list.
The Legend of Zelda: Ocarina of Time - Lost Woods / Saria's Song
Another well known Zelda song, this time from Ocarina of Time. You may also remember it as an alternative song for Great Bay in Melee. The song's upbeat tune and positive mood are a good fit for this stage.
The Legend of Zelda: Link's Awakening - Tal Tal Heights
An orchestrated version of this song would be excellent on this stage. Both places being high in the sky and this song, even in 8-bit greatness, captures that feeling quite well. One of my favorite songs from the franchise that feels quite adventurous just like the Main Theme and Dark World.