Not best films per se, but favorite actual song/dance numbers within a film that just make you all warm and fuzzy inside.
Wise Up - Magnolia
We Go Together - Grease
The Origin of Love - Hedwig and the Angry Inch
Thriller - 13 Going on 30
Bye Bye Life - All That Jazz
I'm Thru With Love (Woody and Goldie on the river bank) - Everyone Says I Love You
Llorando - Mulholland Dr.
Every Sperm is Sacred - The Meaning of Life
It Don't Worry Me - Nashville
Say it to Me Now - Once
Rockerfeller Skank - She's All That
Soul Bossa Nova (Opening Credits) - Austin Powers
What are some of yours?