I'll take the first song I taught myself on the Piano: Aerith's theme, such a memorable piece of music, and that scene when Cloud laments her death, never failed to send shivers down my spine:

Cloud: ...Aerith.

Cloud: This can't be real!

Sephiroth: Do not worry. Soon the girl will become part of the Planet's energy. All that is left is to go North. The 'Promised Land' waits for me over the snowy fields. There I will become a new being by uniting with the planet. As will this girl...

Cloud: ...Shut up.

Cloud: The cycle of nature and your stupid plan don't mean a thing.

Cloud: Aerith is gone. Aerith will no longer talk, no longer laugh, cry...... or get angry......

Cloud: What about us...... what are WE supposed to do?

Cloud: What about my pain?

Cloud: My fingers are tingling. My mouth is dry. My eyes are burning!

Sephiroth: What are you saying? Are you trying to tell me you have feelings too?

Cloud: Of course! Who do you think I am!?

Sephiroth: Ha, ha, ha...... Stop acting as if you were sad. There's no need to act as though you're angry either.

Sephiroth: Because, Cloud. You are...

Jenova: Because, you are...... a puppet.

Cloud: I'm...... a puppet?

Shivers, even now...