If I had to rank the three concert pieces from The Phantom Menace, Attack of the Clones and Revenge of the Sith, I would rank them the following way:
1) Battle of the Heroes - perfectly describes the heavy drama of the last prequel. 2) Across the Stars - a lovely romantic theme that expresses the tragic love of Anakin/Padme. 3) Duel of the Fates - it's the weakest but it is still a riveting action cue.
Across the Stars captivates me every time. That theme was the sole reason I bought the album. Naturally, there was a whole boatload of great material besides that.
I actually think that Battle of the Heroes is the weakest. I remember being very underwhelmed when the score was released at that track. Anakin's Theme, Across the Stars and Duel of the Fates are all far superior.