You mean "Cheek to Cheek"? Love that one too. I love a Fred Astaire number and how the skirt flows freely to the music.
I also agree with anyone who said these:
All of "A Chorus Line"
All of "Movin' Out"
All of "Wedding Singer"
"Supercal...", "Step in Time," and "Jolly Holiday" from MARY POPPINS
Here's my additions:
The move in SPRING AWAKENING that starts out in super slo-mo at the beginning ("Mama Who Bore Me") but then works its way up little by little through "Mirror Blue Night" and then becomes absolutely frenetic during "Totally F****d"
All of "West Side Story"
All of "Swing Time"
Jerry Mitchell's "La Cage Aux Folles"
Most of LEGALLY BLONDE (mainly Whipped into Shape, but in time I got used to the step-dancing in "Legally Blonde Remix")
All of "The Producers" (yes, including the walkers and the Busby Berkeley-style swastika)
All of "Hairspray" (I did the whole "You Can't Stop the Beat" dance from my seat, but I was all the way up in the nosebleed section, so nobody noticed)
"How could she just suddenly, completely disappear into thin water?" - The Little Mermaid