I'm gonna agree with a lot of ppl and my top 2 are definitely Chitty and You Can't Stop The Beat. 30/90 is actually climbing up with those two, but not quite there.
Now in terms of CDs...the ones that always seem to be in my head are Miss Saigon, J&H, and more recently DRS. Let's see some specific songs...Heat is On in Saigon, Why, Morning of the Dragon, I Swear I'll Give My Life For You, Bui Doi, American Dream...Take Me As I Am, His Eyes, Dangerous Game, Alive, Someone Like You...Give Them What They Want, Love Is Your Legs, Like Zis Like Zat, Nothing is Too Wonderful To Be True...these DRS songs were stuck in my head most of my disney world trip. Usually I'll get a CD stuck in my head of these 3 and they just kind of alternate taking turns in my head.
"If there was a Mount Rushmore for Broadway scores, "West Side Story" would be front and center. It snaps, it crackles it pops! It surges with a roar, its energy and sheer life undiminished by the years" - NYPost reviewer Elisabeth Vincentelli