Onimusha/Awesome

The ending FMV. Samanosuke unleashes his Oni form and proceeds to seriously kick Fortinbras' ass, including slicing the enormous demon's arm in two, from hand to shoulder.

The opening FMV.
Any duel with Gogandantess. Especially the last one.
- Even more so if the player opts to defeat him without deactivating his shield.
The final battle against Nobunaga in his demon form inside a flesh room. Goes over the top in the second phase, where Jubei transforms into the Ultimate Onimusha complete with Arm Cannon.

Jubei: "I must.... believe in the Oni... they will guide me!"

"The enemy awaits at Honnoji Temple!". And this is the very first level. The music really adds to it.
Jacques using the bike to reach the sailing Genma Ship.
Samanosuke use the Oni Army Globe to summon a huge army of ethereal Oni soldiers which engage the Genma Army in battle. And you fight your way across the battlefield towards Azuchi Castle while an epic tune plays. The fact that you're using Jean Reno makes it more awesome.
The final boss battle against Nobunaga. Especially when Samanosuke finally seals him away forever.
"Samanosuke... kick his ass."
Jacques' revenge on Ranmaru after the latter mortally wounds Henri. To elaborate - he punches him to death.
Samanosuke's assualt on Guildenstern's lab at the zoo, in order to rescue Michelle and Henri.
Samanosuke vs. Gargant. Full stop.
Heihachi's defiance of Vega Donna. Doubles as a Crowning Moment of Funny.
Samanosuke vs. Ranmaru... on top of the Eiffel Tower.
Jacques vs. Nobunaga.

The Opening. Fullstop.
Dark Oni Soki against Genma Colossus. See also Curb Stomp Battle.
Soki bitchslapping Munenori Yagyu after their first fight complete with Ironic Echo.

Soki:" I forgot to tell you: I'm one enemy you don't want to make either.

After the first fight with Yodo/Ofelia, Ohatsu pays her back for Mind-Screwing her by unloading the whole gun in her head.
Chapter 16, Boss Battle: Jubei vs Munenori.
The Final Battle. All of them.