I'm not sure on how many endings there are...
I know there's one that shows the Calm lands for a couple seconds
One with Tidus on besaid and at the Zanarkand Ruins...
and one where she just flies off and that's that.

Are there any else? (please include a short description spoiler free)

I didn't like the story too much...but the endings were in proportion with the rest of it.

Though X was my favorite ending.