This series is just full of these. One of the main reasons why the games are popular is also probably credited to how kick ass the character Leitmotifs are.
First of all, the anime characters all have their openings and other music for their own Leitmotifs. Many of these are awesome in and of themselves. See the relevant Anime sections for those.
Toki o Koete (aka Crossing Through Time) is a VERY inspiring heroic piece, and it gets better in SRW F/FINAL remixes. In fact, even the basic midi version in SRW 3 was enough to raise the excitement level by a considerable margin.
The Sword That Cleaves Evil, the theme of Sanger Zonvolt. When you hear it, you will always get the feel that some poor evil chap is going to get cleaved. With a very big sword.
Gate of Magus, Zengar's original theme, later adopted by Wodan Ymir, his cyborg memory clone. The image of a desperate struggle between good and evil is conjured into the mind of the listener by the interplay of flute and organ music, with the exchange of blows represented through the cacophonous roar of trumpets and copiously ominous percussion.
Similarly, Zengar's second theme for Dygengard/Daizengar is so awesome it breaks CLEAVES the fourth wall.
Everywhere You Go, the theme of Ryusei Date. This is apparently so awesome that before Bandai Namco took over Banpresto, this song is used as the theme song of the company.
Back in the day when Mazinkaiser is still a SRW exclusive unit, it dont have the currently used themesong from the OVA. However Banpresto make an exclusive themesong for it which isnt any less awesome, here is the one used in the game, and this one is a vocal version by Ichiro Mizuki
Dark Knight, Axel Almer's theme. Made of pure ass kicking (which will be delivered straight to your face, if you're unprepared)
Ash to Ash, Lamia Loveless' theme. Enchanting and cool in a way, portraying the change between a cold-hearted soldier into a protector.
Neppu! Shippu! Cybuster!, the Hot Blooded theme of Masaki Andoh. To be honest, the Lord of Elementals has a lot of catchy awesome songs, which will turn out awesome when they get ported into OG 3. A sample of their tracks can be seen here.
Forgetting the OVA version? Unforgivable. The wind is calling, someday you'll hear its voice.
This troper doesn't even likeSoul of Steel (at least in the GBA games), yet he still finds it to be Crowning Music of Awesome when the SRX first shows up in each game.
Add lyrics, and you have a song people learn Japanese just to sing along with. Really, that applies to just aboutany songin the series. And they tend to be given lyrics often.
The troper feels GONG is one of the greatest songs ever made, both in terms of the melody's essence, as well as the the context of the song in relationship to the game it appears in. See the lyrics for yourself.
Although it can be argued that Skill is the most popular JAM Project song, used as finale of many of their consents concerts, or used for an encore. Both are great, and like asking a parent to pick their favorite child to decide what one is the best.
Opening songs are most of them well done. Don't forget to check out So Close Yet So Far.
The songs of JAM Project are pretty much the incarnation of this whole trope, having the power to turn just about anything into a Crowning Moment of Awesome.
Fans have made this powerfully clear in a number of AMVs made over the years. One powerful example: The end of the opening scene to Alpha 3 shows the Alpha Numbers staring down an impossibly huge number of Balmarian ships, and charging towards them, eventually getting buried in an endless swarm of Aerogaters. The actual music makes this scene look rather doomed and depressing. Overlay the end of Skill to it, however, and you absolutely cannot believe for an instant that they aren't going to emerge victorious. (Or hold back the Manly Tears the end of that song forces from you.)
Black Stranger, the theme of Asakim "Not-Masaki" Dowin. Maybe he's a complete depraved bastard, but boy, does that song just kick ass.
Shippu Jinrai, the theme of DaiRaiOhDyLIOH Unit DGG-XAM3 Custom. You're not officially a Dynamic General Guardian until your theme song is capable of kicking an opponent's ass on its own.
And since you bring it up, we also gotta mention Platinum Lucifer/Fallen White Angel, Excellen's theme. A cheerful, energetic piece, just like a cheerleader. And since you're probably now imagining Excellen in a cheerleader's outfit, you're welcome.
King of Ruin, the theme of Perfectio, the final boss of SRW Destiny. It may be a redundant boss, but GOD DAMN IT! That music is just way too epic to not enjoy!
The theme for the Ruina Generals is just the kind of music you listen to for that special urge to kick their asses to hell and back as well.
And for additional awesome, the vocal version, used in Episode 10 of The Inspectors, sung by Latooni & Shine's seiyuu.
Bullet Striker, the theme of the Super Robot Wars W's Valhawk.
Just One Chance, used for the final attack of SRWW's Valzacard, also fits the bill.
Determination, the theme that plays when Mihiro gets to pilot the Valhawk solo, is shockingly full of win and may be the best original piece in the game (tellingly, it's the longest, as the only piece to clock in at over two minutes a loop). It's gentle enough to match a character like Mihiro but forceful enough to match the phat asskicking she's capable of handing out, and it's worth keeping on the Valhawk even when you get Kazuma back.
It's kept on the Valstork too, so you can still hear it by using Shihomi, after she succeeded Blessfield. This quite possibly makes it the Ardygun family theme song.
The Final Boss theme Eternal Memory despite being upbeat for a final boss.
The Gunleon starts with a pretty badass theme in Land Crasher. And then, the Magna Gunleon transforms into existence, and you're given the absolutely awesome Makenaize! Gunleon. You're about to be wrenched straight out of existence if this one comes on your sound system.
Shooting Star, Cut Through The Night!, the theme of Ibis Douglas. It certainly conveys the gentleness and willpower of one certain clumsy Captain Crash to completely evolve into a kickass pilot who can finally spread her wings and soar high into the sky and reaching her dreams... through a kickass music!
Also Edax which sound fit their nasty mech nicely.
Cherry Blossom Illusion, Ouka Nagisa's theme, brings to mind a bird soaring on the wind. In a way it's almost heroic but her situation is a rather ironic one. This only makes it even more satisfying when she fights for your side.
Kurogane Arrange Music made a great version of her theme
Dark Prison, the theme of Masaki's rival Shuu Shirakawa. The O Gs remake is kickass on its own, but the Alpha Gaiden version also delivers the ominous feeling of what kind of twisted person Shu is, a true Magnificent Bastard kept in prison for so long, his release WILL spell disaster on his enemies and your team.
The song Machine Soul was used to promote SRW MX, and later remixed to promote OG 2 and OGS. Another fine example of great SRW music.
Not original to SRW, but: Let's Go Gekiganger 3 was included in Super Robot Wars W. So you can have it playing in the background when Gai Daigouji does all his awesome moves.
When you hear Armageddon, you know that you're in for a ride through hell. This is a boss level, and you can expect your units collective asses to be handed to themselves.
Doujin remixes of Super Robot Wars are relatively few and far between, but some are kickass in their own right. Have an example in moAbi's Steel Beowulf.
The rallying themes from O Gs and OGG. When it looks like the enemy's about to win, the rallying themes kick in and the player and the characters get a Heroic Second Wind. And to add more awesome, there are orchestrated versions of past SRW themes, and get used in the endgame of '"The Inspectors'':