"Crosswise" by TM Revolution, the opening to the first game in the series, and it's still a cash as hell theme. Bonus points for a snippet of it being played in Sengoku Basara X when a character does a Basara K.O.
"Naked Arms", the opening to the third game (or Samurai Heroes). Yes, that's English they're speaking. Try to understand it if you can.
"FLAGS", the Chronicle Heroes opening (sucks that copyright took away the audio to the actual opening). Again, despite it not being a main installment, it was used as the theme of the the anime movieThe Last Party.
"Utage", the opening to SB3's expansion game, Utage. Funny, it was supposed to be an attempt to make the bummer story more lighthearted...and then they re-introduced MatsunagaHisahide...
"wE aRE", the opening to the HD Collection, and freakin' amazing. You must not have a sense of flair if you don't replay that remake of the Power Trio's flight scene from the second game's opening at least once.
"Count ZERO", the opening to the fourth game. Easily the most epic opening cinematic in the series to go with it to boot, being a full-blown Space Battle representing the Big Bang Theory - or in this case, Sengoku Genesis.
"Sword Summit", the anime's second Op, is no slouch in the awesome department either.
You thought you killed him? Yeah, he simply comes back to life, as strong as before, but this time his main theme "The Abyss" plays to show just what deep shit you're now in. With the guitar riffs and powerful vocals, it's spine-chillingly epic.
The Utage remix is just as sinister for someone who sets fire to all in his way.
Ashikaga Yoshiteru's theme is utterly glorious, with an amazing choir and orchestra of instruments driving the song. Easily the most regal theme in the series for the Shogun of Japan.
Fuma Kotaro arguably has one of the best themes in the series - not just in respect to character themes, but in respect to the series' music overall. There's a reason why his theme is one of two themes that hasn't changed at all since his debut, the other being Oichi's theme ("Sleeping Scarlet Flower").
"Enraged Soul" - This is the duel theme that plays between characters who are related but aren't archetypal rivals. Interestingly enough, this plays for Ieyasu vs Mitsunari scenarios instead of BASARA despite them officially being rivals, which just goes to show how much deeper the animosity runs in comparison to Masamune and Yukimura. note Plays for Ieyasu vs Mitsunari, Keiji vs Hideyoshi, Masamune vs Mitsunari, Motochika vs Mitsunari and Mitsunari vs Yukimura It also plays when you face Kasuga one-on-one in story mode (with the exception of Keiji's drama route), who is out for blood because Kenshin has been killed.
"Bet on the Future", the Sakon vs Katsuie theme. It also plays in Ieyasu vs Motochika fights, which makes sense since Motochika needs to make a decision whether to embark on his dream and set out to sail the Seven Seas or help Ieyasu conquer the country.
Sengoku BASARA 3
"Will" is a very intense theme, which is fitting for what is supposed to be the final battle in the Sengoku era.
"The Red Bell", a solemn remix of Magoichi's theme that often play at the end of her routes.
"Life", so epic, and yet it's just one of the map themes in the third game!
"Friendship Revives", which plays in any of Motochika's routes where he finds out Ieyasu wasn't behind the Shikoku massacre.
"Farewell, Friend" plays at the end of Motochika's red route, where he kills Ieyasu for something he didn't do, but Ieyasu took his anger anyway as well as in many of Keiji's routes, particularly when reminiscing about Hideyoshi.
Osaka Siege in general has music that is great for trying to cinch the castle that was once Hideyoshi's:
"Omi - Sawayama Castle", which is one of the most ominously driven themes in the game, and acts as the theme to Mitsunari's castle stage.
"Kaga - Maeda Keiji's Festival", which is the first of a three-part theme that plays at the entrance of Keiji's Kabuki Matsuri stage. Doesn't sound much like a war theme until you claim a base...
...and Toshiie enters the fray, at which point "Maeda Keiji's Festival - Dance" kicks in, as a frantic rearrangement of the first part of the theme. It gets you pretty hyped for a brawl with the Maeda clan, and then once you defeat Toshiie or take out another base, Matsu enters the battle...
...and "Maeda Keiji's Fesival - War" kicks in, which makes the battle even more frantic by adding the chants of festival-goers to the mix and increasing the pace of the music even more. It does really seem like a build-up towards fighting Keiji.
"Genesis" is the general (epic as hell) Genesis march theme, with a pretty touching beginning.
The piano arrangement of "Genesis" which notably only plays in Keiji's route, during his Genesis march when thinking about Hideyoshi or his doubts about being commander of the Maeda army. It also plays when Keiji has to accept the reality that his friendship with Hideyoshi won't come back after beating him in his drama route.
"Heavenly King's Leisure". Ironically, it doesn't sound any happier - in fact, it plays when Katsuie dies in his anime route.
"Otomo - Xaviland", which will make you smile the first time you hear it. It's just...the essence of fun in musical form.
"Remains of Onin". It's a sinister theme, and for good reason - you're fighting on the ruins of a 10 year war that began the Sengoku period. And how fitting that the boss of this area is the Shogun himself.
"Azuchi's Four Lords Gather", an epic piece that plays during the Unifier four-way battle between Nobunaga, Hideyoshi, Ieyasu, and Yoshiteru.
The Battle of Sekigahara themes:
Eastern Sun's theme sounds like one heck of a climactic battle, and is probably the theme that will fill you with fighting spirit the most.
Western Shadow's theme makes it sound like you've really gone and walked into a death battle. While Sekigahara - East makes you feel as though you're fighting in the final act of a war, Sekigahara - West strikes with a ton of urgency that only Mitsunari could give you.