I gotta go with The Asteroid Field from Empire. It's the perfect marriage of music and film, but is also an hugely exciting cue on its own. Perfect in every way.
The Asteroid Field is like Ben's Death and TIE Fighter Attack where I have almost no use for the concert arrangement. The more narrative heavy arrangements in the film are so perfect. They are the most amazing little nuggets of themes and story.
I was also thinking yesterday that as terrific as the pieces for the Hoth battle are, or even the end chases / duels in Empire, nothing can beat The Last Battle from Star Wars.
Do you mean "The Battle of Yavin"? My favorite tracks are "Ben's Death and TIE Fighter Attack", "The Asteroid Field", and "The Battle of Yavin" My favorite theme is The Force and favorite instance of its use is during the Death Star trench sequence when it is heard with the words "Use the Force Luke!". The music along with the visual of what Luke sees speeding down that trench made for an unforgettable moment.
Hands down The Throne Room and End Title, Princess Leia's Theme, and The Finale from TESB. Followed closely by The Tie Fighter Attack and The Asteroid Field (score tracks, not concert arrangements).