To be specific, I'm talking about the part at the beginning of the movie with the credits rolling over it, which usually has the theme tune playing. You know, like the battle at the start of the first movie against the Donphan guy.
For me, it has to be Spell of the Unown. A full six on six battle, gorgeous animation, nostalgic music and a more realistic fight. They don't just let Ash steamroll it 6-0, and they've learnt Ground types are immune to Electricity! Love the way it shows off the character of the Pokémon, like Totodile's little dance and Chikorita's lovey dovey moment, and Lisa dancing with her Butterfree.
If you can't remember the openings, here's a brief rundown:
Mewtwo Strikes Back: Ash battles Raymond.
The Power of One: The gang let their Pokémon out for a spell during a boat trip.
Spell of the Unown: Entei: Ash battles Lisa.
Celebi: The Voice of the Forest: Ash battles Dundee.
Heroes: Latios & Latias: Ash and Misty compete in a race around the canals.
Jirachi: Wish Maker: Workers set up a fairground.
Destiny Deoxys: A research expedition observe Walrein, Sealeo and Spheal under the Northern Lights.
Lucario and the Mystery of Mew: Ash competes in a tournament to become the Hero of the Year.
Pokemon Ranger and the Temple of the Sea: A troupe put on a display using water and psychic powers.
The Rise of Darkrai: The gang are shown around a city, with brief battles against the fully evolved gen 4 starters.
Giratina and the Sky Warrior: Abstract images of particles, snowflakes, bubbles, crystals and CGI Pidgeys.
Arceus and the Jewel of Life: Ash and Dawn tag battle against Kato and Kiko.
Zoroark: Master of Illusions: Abstract images of letters, roots, a forest, veins in a leaf, a tree, a crack in ice leading to magma, etc.
White: Victini and Zekrom: The gang participate in a tournament through the streets of the town. Hydreigon is shiny.
Black: Victini and Reshiram: The gang participate in a tournament through the streets of the town. Golurk is shiny.
Kyurem vs. The Sword of Justice: The Pokémon play around on a train.
Genesect and the Legend Awakened: The gang let their Pokémon out to play with the wild Pokémon in Pokémon Hills.
Diancie and the Cocoon of Destruction: Ash battles Astrid whilst Diancie is chased around town.
Hoopa and the Clash of Ages: The World of Pokémon intro, showing various legendaries being depicted in a frieze.
Volcanion and the Mechanical Marvel: Ash battles Clemont.
I Choose You!: Ash's early journey with Pikachu and catching Caterpie, a brief battle with Machop.
The Power of Us: A whistle-stop tour of Fula City, showing the characters from the movie.
Mewtwo Strikes Back - Evolution: Ash battles Raymond.
Secrets of the Jungle: Dada trying to look after baby Koko.
For me, it has to be Spell of the Unown. A full six on six battle, gorgeous animation, nostalgic music and a more realistic fight. They don't just let Ash steamroll it 6-0, and they've learnt Ground types are immune to Electricity! Love the way it shows off the character of the Pokémon, like Totodile's little dance and Chikorita's lovey dovey moment, and Lisa dancing with her Butterfree.
If you can't remember the openings, here's a brief rundown:
Mewtwo Strikes Back: Ash battles Raymond.
The Power of One: The gang let their Pokémon out for a spell during a boat trip.
Spell of the Unown: Entei: Ash battles Lisa.
Celebi: The Voice of the Forest: Ash battles Dundee.
Heroes: Latios & Latias: Ash and Misty compete in a race around the canals.
Jirachi: Wish Maker: Workers set up a fairground.
Destiny Deoxys: A research expedition observe Walrein, Sealeo and Spheal under the Northern Lights.
Lucario and the Mystery of Mew: Ash competes in a tournament to become the Hero of the Year.
Pokemon Ranger and the Temple of the Sea: A troupe put on a display using water and psychic powers.
The Rise of Darkrai: The gang are shown around a city, with brief battles against the fully evolved gen 4 starters.
Giratina and the Sky Warrior: Abstract images of particles, snowflakes, bubbles, crystals and CGI Pidgeys.
Arceus and the Jewel of Life: Ash and Dawn tag battle against Kato and Kiko.
Zoroark: Master of Illusions: Abstract images of letters, roots, a forest, veins in a leaf, a tree, a crack in ice leading to magma, etc.
White: Victini and Zekrom: The gang participate in a tournament through the streets of the town. Hydreigon is shiny.
Black: Victini and Reshiram: The gang participate in a tournament through the streets of the town. Golurk is shiny.
Kyurem vs. The Sword of Justice: The Pokémon play around on a train.
Genesect and the Legend Awakened: The gang let their Pokémon out to play with the wild Pokémon in Pokémon Hills.
Diancie and the Cocoon of Destruction: Ash battles Astrid whilst Diancie is chased around town.
Hoopa and the Clash of Ages: The World of Pokémon intro, showing various legendaries being depicted in a frieze.
Volcanion and the Mechanical Marvel: Ash battles Clemont.
I Choose You!: Ash's early journey with Pikachu and catching Caterpie, a brief battle with Machop.
The Power of Us: A whistle-stop tour of Fula City, showing the characters from the movie.
Mewtwo Strikes Back - Evolution: Ash battles Raymond.
Secrets of the Jungle: Dada trying to look after baby Koko.