There are 8 attractions at Disney's Hollywood Studios we rate as "Not To Be Missed":

Not To Be Missed at Disney's Hollywood Studios
Animation Courtyard Voyage of the Little Mermaid
Echo Lake Star Tours: The Adventures Continue
Pixar Place Toy Story Midway Mania!
Streets of America Muppet*Vision 3D
Studio Backlot Tour
Sunset Boulevard Fantasmic!
Rock 'n' Roller Coaster Starring Aerosmith
The Twilight Zone Tower of Terror

Not To Be Missed Attractions at Other Parks