"Aniron" aka "Aragorn and Arwen", by Enya. If you weren't sucked into Middle-Earth before this came on, you are now. One of the most ethereal songs ever written? Possibly. The beautiful Evenstar is also worth mentioning.
The fanfare that plays as Gandalf reveals the halls of Khazad-dûm. Simultaneously triumphant and desperately sad, what with the glory of the place being long gone.
"The Bridge of Khazad Dum" is an amazing track. It starts with a grand fanfare of the fellowship, and then there's the ominous, pants-wetting build-up to the Balrog's first appearance. Apparently a bunch of Maori rugby players chanting in Khuzdul (Dwarvish) sounds just like the Choirs of Hell. The chants combined with the exciting music create an epic song. It then ends with a sad choir when Gandalf falls to the Balrog.
"May It Be" by Enya. Makes for a memorable conclusion to Fellowship of the Ring, and will keep many audiences in their seats while the end credits roll.
The Two Towers
"Foundations of Stone",this song plays at the very beginning of The Two Towers. It starts out with a regal tone with a hint of "Gollum's Song" added in. It then transitions into an epic variant to the Khazad Dum theme during Gandalf the Grey's last stand with the Balrog.
"The White Rider" starts in a dramatic fashion as Gandalf makes his return, it then transitions into the lovely theme of Shadowfax. The theme also makes a grand reappearance when Gandalf along with the forces of Eomer come to aid in the Battle of Helms Deep.
Very little can beat listening to "Isengard Unleashed" while driving through a forest on a foggy day.
The music when the Elves march to the rescue at Helm's Deep. That ethereal, contemplative theme, reworked into one of the most badass marches ever? Awesome. (Starts at 3:02)
The music that plays at the climax of the Battle of Helm's Deep - with the cavalry charging down the slope towards the black mass of Orcs. "The sun is rising towards the heaven. A beautiful silver waterfall of men and horses will soon sweep away the darkness. We won't ever see its like again. Not like that."
The lovely motif of Rohan, the violins used within are amazing. Some of its best uses would be when Theoden is free from Saruman's hold and when the people arrive at Helm's Deep.
Even his evil themes are awesome. The pounding "Isengard/Uruk-hai" music simply screams badass, and the raucous theme for Mordor is just plain warped, which makes it perfect.
The beautiful music that plays when Sam gives his inspirational speech to Frodo.
The song played during the closing credits of The Two Towers: "Gollum's Song" is an incredibly touching and moving piece about none other than Gollum, originally written for Björk and sung by Emilliana Torini. If you didn't feel for Gollum's tragic story before, you almost certainly will after hearing this song.
The Return of the King
"The Steward of Gondor" starts out with a heartbreaking melody as Faramir leaves to face the enemy, knowing he will not survive. Then we get to hear Pippin sing a beautiful song to Denethor. The song soon begins to grow more ominous as we watch Faramir about to get killed by the orcs.
Every iteration of the Rohan theme is great, but the one that can get to you the most is the last 30 seconds of "The ride of the Rohirrim". An entire nation of horse-riding badass warriors, saddling up fortherescue? HELL. YEAH. That glorious music with the old recording of The Professor Himself reading that sequence? A mashup just waiting to happen.
The variation of Éowyn's theme when she speaks with Aragorn right before he departs to take the Paths of the Dead. It was played on a unique double fiddle constructed specifically for the film. It differs from the Hardanger fiddle used elsewhere for the Rohirrim in that while the Hardanger has four played strings and either four or five sympathetic stringsnote the played strings are actually bowed, while the sympathetic strings are allowed to resonate freely the double fiddle has 8 strings arranged in pairs, with each pair being bowed together. The result is hauntingly, uniquely beautiful.
The heroic and marvelous theme of Minas Tirith perfectly captures the glory of Gondor.
The Lighting of the Beacons is an amazing track all the way throughout. When Pippin lights the first beacon, the song transitions into an chaotic and exciting melody like a wildfire spreading. The music then bursts into the confident and glorious theme of Gondor.
The track "Return of the King" is a long yet heartwarming song that plays when Frodo is reunited with the Fellowship, Aragorn is crowned King, and the Hobbits return to the shire. During Aragorn's Awesome Moment of Crowning we hear a lovely elvish song sung by Aragorn followed by a powerful rendition of the Hobbit's theme when everyone bows down to Frodo and company.
The music which plays after the army of the West is surrounded in The Return of the King: The Black Gate has opened. Aragorn, the fellowship (minus Sam and Frodo, of course), and the entire military might of men are surrounded. Everyone's looking freaked out. Then, Aragorn simply says, "For Frodo," and the most epic choral rendition of the Fellowship theme kicks in as our heroes charge into battle.
In the extended soundtrack, The Crack Of Doom. It is basically glory incarnate played during the destruction of The One Ring. Although the finale of the song is more quiet and heartbreaking, as everyone begins to suspect Frodo and Sam did not survive.
The Cut Song "Arwen's Song", by... Liv Tyler(!), repurposed as "Houses of Healing", a song about Éowyn, and she definitely has her father's chops... It was replaced by the song "Twilight and Shadow" by Renee Flemming during Arwen's vision in the forest of her future son, which Figwit so rudely interrupts.
"The Black Gate Opens". Dark and ominous and foreboding and all that, then the short quick wistful Concerning Hobbits when Sam is asking Frodo if he remembers strawberries and it's all so sad, but then! Then the music crescendos and Sam hoists Frodo on his back and it's so very awesome.
In addition to the Tear Jerker feeling of "Into the West", it's been cited that Fran Walsh, one of the writers for the song, was inspired to write it by Cameron Duncan, a teenaged amateur filmmaker who was dying of osteosarcoma (bone cancer) at the time of filming.
Shore managed to put one of his most tear-inducing, spine-tinglingly beautiful moments about 23 minutes into the Fellowship of the Ring end credits.
"My Dear Frodo". You have this sweeping orchestral opening, brand spanking new graphics for New Line Cinema, the promise of a true epic...and then the music segues into "Concerning Hobbits". Especially notable during the film itself, as opposed to the soundtrack. If that's not a warm welcome back to Middle Earth, nothing is.
The music that plays during the Goblin Chase is a mix of deep sounding drums and heavy chanting that rivals the Bridge of Khazad-dûm scene in Fellowship of the Ring. The music during the Orcs pursuit of Thorin and company earlier in the film is also exciting.
The first appearance of the Ring in The Hobbit is heralded by the Lord of the Rings theme, played on a few wavering strings. Not a super bombastic part of the score, but an absolutely perfect moment that sends chills down your spine.
The ethereal piece when the Eagles rescue the Dwarves from Azog's forces, the choir is simply gorgeous. Sadly, this was not used in the film.
In The Desolation of Smaug, witness the awesomeness of Tauriel's exhilarating new theme dueling with Legolas' theme (a reworking of the classic elven themes heard in LOTR) as they race to the rescue of the dwarves during the barrel-riding scene. The love theme between Tauriel and Kili titled: "Feast of Starlight" is a heavenly piece that carries a lovely choir.
The majestic music that plays during the scene where Thorin and company are led into the Woodland Realm.
Billy Boyd (Pippin) getting the credits song, "The Last Goodbye" from The Hobbit: The Battle of the Five Armies. It plays over a similar credit sequence that ended the LOTR trilogy with each character getting a sketch. Listen closely and you hear that it clearly samples "Into the West" from the end of Return of the King. But whereas "Into the West" had a definite feeling of "This is the end" about it, "The Last Goodbye" somehow conveys the notion of "This was just the beginning" and just makes you want to pull down The Fellowship of the Ring and start watching even if you've just gone through nine hours of The Hobbit.
The inspirational and heroic theme of Ironfoot from Battle of the Five Armies.
Smaug's ominous motif sometimes uses unique instruments like flutes and bells to a menacing effect. In contrast, the theme of Erebor is majestic yet somber, depicting the long lost glory of the Dwarves.
The brief but glorious reprise of the "Last March of the Ents" that is used when the eagles arrive in the final battle.
"Guardians of the Three" is an excellent track that weaves together the themes of Mordor and the Elves, the best part of the track is the heroic portrayal of the Rivendell theme that plays when Elrond joins the fight.
The somber yet glorious theme of Erebor that plays when Thorin and company finally reach the Lonely Mountain.
The music during the final battle of Erebor is filled with many epic moments such as when Ironfoot joins the battle, the badass chants during the men of Laketown and the dwarves Lock and Load Montage, and the powerful rendition of Thorin's theme as he leads the charge out of the Erebor.
The Requiem for a Tower music (in the second half of the Two Towers trailer), which is SO epic it was copied for half the music videos on Youtube.
More trailer music for Return of the King: The reprise of the Gondor theme Howard Shore arranged based on Siren Cues' "Epicalypse". When a trailer makes you shed Manly Tears over its awesomeness, you know the movie itself will be something special.
The whole trilogy can be considered a Crowning Moment of Awesome for Howard Shore. The man wrote twelve hours of music, much of it involving the entire orchestra, over just three years. And every bit of it was fantastic.