There are 9 attractions at Disney California Adventure we rate as "Not To Be Missed":

Not To Be Missed at Disney California Adventure
Cars Land Radiator Springs Racers
Grizzly Peak Grizzly River Run
Soarin' Over California
Hollywood Land Disney's Aladdin - A Musical Spectacular
Muppet*Vision 3D
The Twilight Zone Tower of Terror
Paradise Pier California Screamin'
Toy Story Midway Mania!
a bug's land It's Tough to Be a Bug!

Not To Be Missed Attractions at Other Parks