Wow, that's a tough pick.
I like Shadowland because of the emotion in it (though I wish they would've kept it in 3/4 time)
Endless Night is a great challenge for my voice, and I sing on it to work on my higher register, but the lyrics are a little odd.
Then He/They Live(s) in You are great. There's a great example of lyrics fitting the music and the music setting the scene.
CYFTLT is amazing on broadway. The only thing I don't like are the awkward dancers in the very pretty instrumental interlude.
Morning Report is a lot of fun to goof off with, but it doesn't stand alone very well.
And I could say a lot more about all the other songs as well. And don't get me wrong, I love all of these songs (I analyze because I care, lol). Overall, though, I'd have to pick He Lives in You as my theme.