1. The battle against Remiel in Tales of Symphonia.
Spoilers abound here, but let's just say the combination of the song "Beat The Angel" and the preceding scene make this one of the most amazing battles ever.
2. The series of battle against Sin while on the airship in Final Fantasy X.
Seven people and a dinky little hunk of ancient metal against a giant monster. Plus perfect music during the battle.
3. The Delphinus versus Zelos in Skies of Arcadia.
The final airship battle of the game is by no means easy or short, and a single mistake means you go boom. And, of course, good music.
4. The Hero's duel with Luca Blight from Suikoden II
Luca Blight, the enemy for most of the game, has finally been cornered-and you finally get to kill him. It's because of him that several cities and towns were destroyed, among other spoilerific events. He's powerful too-he gets three boss battles prior to this, with six people in each of your parties against him. Great music, too.
5. The battle with Neclord from Suikoden II
The hated enemy of one of the most importent NPCs in the game, as well as one of the few who get their own opposing sword. And his own music track, "Gothic Neclord". See a pattern yet?
Honorable Mentions:
1. The first battle with Magus in Chrono Trigger.
Need I say more?
2. Samus versus Mother Brain in Super Metroid.
Hyper beam ftw.
3. Doomsday Zone
...you even had to ask?
4. The battle with Atma/Ultima Weapon from Final Fantasy VI
Feeble creatures, go!
5. The battle with Yunalesca from FFX
The same reasons as the battle with Remiel, basically.
And last, but not least...
0. The battle against the five pumpkin bosses from Final Fantasy XII
Ankle high demons who've been keeping the tunnel into Archadia from being used. You hear stories about how fearsome they are, and you walk into a room, and these little tiny things are running around, making squeaky noises. You sit there. You laugh. You look up, and you realize you're half dead.
