Genesis Countdown - Star Trek II All Systems Go, The Launch - Apollo 13 Stealing The Enterprise - Star Trek III Betrayal and Desolation - Braveheart Samuel's Death - Legends of the Fall
So many to choose from...but the one that sprang to mind immediately when I read your question is the car scene and subsequent training session in "The Karate Kid".
Actually that entire cue (titled "From Master to Student to Master" on the OST) is among the very best Horner has written, in my opinion.
When you get right down to it, I have to admit that Horner is my favorite composer. That's going by how often I keep returning to three CDs; the numbers don't lie.
Favorite tracks on those discs:
Genesis Countdown - Star Trek II The Launch - Apollo 13 Rose - Titanic
"Revenge" from Braveheart "Revenge" from Legends of the Fall
No joke man...those twin revenge cues play out so skillfully and hauntingly in both films, scored for films with directors who expertly staged those particular scenes. The music and visuals for those two scenes are powerfully and intricately woven together.