किसका चेहरा अब मैं देखूँ

An interesting way to express how each lover has come to choose the other.

नीला आसमाँ सो गया (male)

It is rather rare that an actor or an actress also provides the singing based on a classical raag. Amitabh Bachchan does this well here. A musical pun, in a female voice later in the story, recounts the heartbreak.

Right Here Waiting

I had heard this song some years ago, and was pleasantly surprised to find it on YouTube.

This song describes the sentiment when lovers [have to] drift apart. The instrumental melody itself is very hummable. This song must have been so popular that it has garnered a Wikipedia article.