To be blunt, most movies.
Books...it depends. Books are rarely trilogies anyway.
If it's a new author who isn't sure she will ever get anything published after this...usually the first book is the worst, actually, because she's still finding her writing style.
If it's an established author confident in getting all three books published, and who just happens to plan a trilogy, it...actually probably still tends to be the third book that's the best (no cliffhangers, the big climax) though it can sometimes be the first just due to the nature of the story (His Dark Materials).
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Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision