Kermitu Kleric Katie
KULT OF KERMITU
First of all, before any of you ask where J-E-N-O-V-A is, know that I'm not counting it because Jenova is moar of a plot device than an actual character.
Anyway, I'm going with Tifa's theme. One-Winged Angel is close second though.
Tifa's Theme: Tifa's theme. Plays during significant Tifa scenes, sych as her flashbacks, and in 7th Heaven before the party leaves to attack Mako Reactor 5.
Barret's Theme: Barret's theme. Plays in significant Barret scenes, such as your gondola ride with him, and also plays as the background to Sector 7 and 7th Heaven after Cloud agrees to attack Mako Reactor 5.
Shinra Company: The theme for the Shinra Electric Power Company. Plays during cutscenes involving them, and outside their HQ.
Turks' Theme: Theme of the Turks. Plays in any room or cutscene they appear in.
Don of the Slums: Don Corneo's Theme. Plays in his mansion.
Red XIII's Theme: Red's theme. Plays when he introduces himself to the party.
Rufus' Welcoming Ceremony: Rufus' theme. Plays in Junon from said welcoming ceremony to the end of disc 1.
Cait Sith's Theme: Cait's theme. Plays when you first meet him and in prominent scenes featuring him.
Descendant of Shinobi: Yuffie's theme. Plays upon meeting her and during prominent scenes with her.
Those Chosen by the Planet: Sephiroth's theme. Plays in Shinra Mansion and during the final "battle" with him.
The Nightmare Begins: Vincent's theme. Plays in the basement of Shinra mansion, when you meet him, and during Lucrecia's flashback.
Cid's Theme: Cid's theme. Plays when first meeting him and during prominent scenes featuring him.
Aerith's Theme: Aerith's theme. Plays when she dies, during Elmyra's flashback, and when the party remembers her death on disc 2. Also, plays when Cloud sees the hand reach out to him, before it turns into Tifa's hand and her theme plays instead.
Birth of a God: Bizarro Sephiroth's theme. Plays when you fight him.
One-Winged Angel: Safer Sephiroth's theme. Plays when you fight him.
Anyway, I'm going with Tifa's theme. One-Winged Angel is close second though.
Tifa's Theme: Tifa's theme. Plays during significant Tifa scenes, sych as her flashbacks, and in 7th Heaven before the party leaves to attack Mako Reactor 5.
Barret's Theme: Barret's theme. Plays in significant Barret scenes, such as your gondola ride with him, and also plays as the background to Sector 7 and 7th Heaven after Cloud agrees to attack Mako Reactor 5.
Shinra Company: The theme for the Shinra Electric Power Company. Plays during cutscenes involving them, and outside their HQ.
Turks' Theme: Theme of the Turks. Plays in any room or cutscene they appear in.
Don of the Slums: Don Corneo's Theme. Plays in his mansion.
Red XIII's Theme: Red's theme. Plays when he introduces himself to the party.
Rufus' Welcoming Ceremony: Rufus' theme. Plays in Junon from said welcoming ceremony to the end of disc 1.
Cait Sith's Theme: Cait's theme. Plays when you first meet him and in prominent scenes featuring him.
Descendant of Shinobi: Yuffie's theme. Plays upon meeting her and during prominent scenes with her.
Those Chosen by the Planet: Sephiroth's theme. Plays in Shinra Mansion and during the final "battle" with him.
The Nightmare Begins: Vincent's theme. Plays in the basement of Shinra mansion, when you meet him, and during Lucrecia's flashback.
Cid's Theme: Cid's theme. Plays when first meeting him and during prominent scenes featuring him.
Aerith's Theme: Aerith's theme. Plays when she dies, during Elmyra's flashback, and when the party remembers her death on disc 2. Also, plays when Cloud sees the hand reach out to him, before it turns into Tifa's hand and her theme plays instead.
Birth of a God: Bizarro Sephiroth's theme. Plays when you fight him.
One-Winged Angel: Safer Sephiroth's theme. Plays when you fight him.