I have many but I guess this is the one that brings a tear to my eye every time.

The Best of times is now. La Cage Aux Folles.

Empty chairs at empty tables. Les Miz

Would you light my candle? Rent

"Frank Mills" from "Hair"

"Defying Gravity" from Wicked

Since I can't pick one (and just limiting myself to this current generation):

1) For Good: Wicked

2) Past the point of no return: Phantom of the Opera

3) Springtime for Hitler: Producers

4) Elaborate Lives: Aida

5) Electricity: Billy Elliot

6) Be our Guest: Beauty and the Beast

7) Good Morning, Baltimore: Hairspray

8) Slipping through my fingers: Mamma Mia

9) The Song that goes like this: Spamalot

and

10) Finale: Les Miz.

"To love another person is to see the face of God."