The song's lyrics are open to some Alternate Character Interpretation which makes it outright hilarious if you think of it as being sung by someone who got owned by Char. And it's even more hilarious when you notice that, in the original series, the soldiers that had occupied Amuro's home were dancing to an instrumental version of "Here Comes Char"!
We later get Oblivion from the same source as Men of Destiny. It uses the exact same instrumental, but rather than simply dubbing the lyrics into English, new somewhat apocalyptic, yet still awesomely GAR, lyrics were written, effectively making it a new song. Also somewhat unique for an English song, it was used in the original Japanese version of the show, and has perfect grammar and pronunciation. And it is freaking awesome.
The movies are no slouch in the OP department either. Case in point: the first movie opens with the awesome song "Metamorphoze" from Gackt, of which there exists a recursive adaptation in the form of the song's official music video, containing actual footage from the movie.
The Pulse of Zeta, which was used as the opening theme for the English version. For some fans it elevated Zeta to the halls of awesome space opera that gives Star Wars a run for its money.
A.E.U.G., which contains a few motifs from "Pulse of Zeta", is no slouch either.
First is "Remind You" from OST II, which is essentially "Unicorn" and "On Your Mark" with English lyrics that sums up the hopes and horrors of the Universal Century.
Also, Cyua's "A Letter" from the first OST (and in a similar vein, "Audrey" from the third) both used in Episode 1 and 5, respectively.
The fourth OST doesn't disappoint either. It includes a remixed version of "Unicorn" as well as sweeping orchestral versions of "RE:I AM" and "Ryuusei no Namida". All while bringing back tracks from all the previous episodes, and even an orchestral remix of "Beginning" from the original Mobile Suit Gundam.
"Last Impression". What starts out calm turns out to be very upbeat, classical and... AWESOME. A fitting end to the AC Saga. This song is always the song for Gundam Wing characters when they appear in Super Robot Wars for a reason. It kicks ass.
"When the Dragon Swims, The World Ends" in the first episode where they introduce the Gundam pilots, and pretty much any song that uses Heero's motif.
...And in celebration of Gundam's 30th anniversary, composer Toshihiko Sahashi created "Believe in Love", which is basically "Just Communication" taken to its absolute zenith, with help from the London Symphony Orchestra.
"PRIDE" (the second opening theme) by HIGH and MIGHTY COLOR. Hell yes.
"Life Goes On" is also filled with awesome, and has more variations used in the episodes than the other ending themes. "Kimi wa Boku ni Niteiru" is also excellent, and is the only ending theme to be used in the series and the Special Editions.
Special mention to Union, played first during Graham Aker's first encounter with the Exia.
Possibility, played during the first battle between the UN Army's GN-X mobile suits and the Gundam Thrones, and again during the 'Break Pillar' incident in Season 2 with Celestial Being, Katharon, Coup d'etat forces, the EFF, and even A-Laws working together to save the cities on the ground in heartwarming and well-animated scene.
Gundam AGE's choice of opening themes are nothing short of impressive. From the upbeat "Asu e" and the hopeful "sharp #" to the epic "REAL" and the moving "AURORA", you'll inevitably find a song to enjoy for a long time.
When "1/48" plays, you know shit is about to get real. This perfectly fits the intimidating nature of the 1/48 Mega Size Zaku II. It's also a striking track during the first half of Reiji vs. Aila in Episode 21.
"Aila" is nothing short of a beautiful, emotional theme for said character. The heartwrenching tone of the song works incredibly well when Reiji learns the truth about Aila.
The first opening theme, "Cerulean" by BACK-ON, which really sets the tone of the show and accompanies Build Burning Gundam's reveal, as well as the Sudden Death round between Sekai and Wilfred in the tournament finals.
Given that Try shares its soundtrack with its parent show, this is to be expected, but the new OST isn't too shabby at all, especially the Jigen Haoh theme (called, appropriately enough, "Clear and Serene").
Special mention goes to the tenth track of OST 1, "These Hands of Mine Shine With a Roar", used in scenes where Sekai is going in for the win. It was most memorably heard in Episode 9, when he has fully assimilated with Build Burning.
One can be sure that awesome things happen when "Bell of Requiem" starts playing. Especially if the G-Portent is on-screen as this song is playing.