Raiders is a classic, but there's absolutely just something incredibly fun about TOD. It's like reading a piece of Pulp Fiction from the 30's; it perfectly embodies that sense of adventure and exoticism present in tales like Doc Savage. The whole heart sequence with Mola Ram is so exciting; as a child, it's one of those things where it frightens you, yet you find yourself peeking through your fingers the entire time, and you just can't look away. I think the character of Indy sort of amplifies that idea of curiosity, with his adventurous spirit and bravery. Every kid wants to be Indy, while watching that. Then, you have the thrilling confrontation on the dangling bridge; Indy versus Mola Ram, head-to-head, and suspended over treacherous waters full of Crocodiles.
God, even thinking about it gets your heart pumping; Indy's awesome sidekick, Short Round, being the perspective character. The whole thing is just an experience.