I'm a huge WDW fan. Everytime I go to the parks, each park, I have a tradition, I have to ride a certain first or see an attraction first before anything other ride/attraction.
Magic Kingdom - Peter Pan's Flight [my mother loves this ride and when she is unable to go I make it a tradition to ride it first in her honor. Of course when she's at the MK with me, we just HAVE to ride it first. No if's, and's or but's]
Animal Kingdom - Africa [the shops, the live entertainment, the buildings]
Epcot - Spaceship Earth [no matter how long the line is, I'll wait for it and it must be my first experience when revisiting Epcot]
MGM Studios - The Pin Trading Store Under the Hat [I have to get a pin from this location and I where it the rest of the day, another tradition]
What are your first ride/attraction must do's before anything else.