Cobalion. I only chipped a way a very small portion of it's health. It was my second or third pokeball after a quickball failed.
Thundurus, half health from a previous encounter and the first pokeball I lobbed at it after I didn't want to accidentally KO it. I wasn't expecting it to be caught so easily.
White FC: Blair 4126 8383 6387
My claims: Joltik, Run Away, Snag Ball, Luck Incense, Shadow Rush.
I managed to catch Terrakion on the first try with a Dusk Ball.
quick ball in the first turn for Zekrom, that stupid dragon didn´t let me hear the music.
My Safari: Psychic, with Abra, Espurr & Gothorita
Team Battle Maison
Claimed: Golett ~ Iron Fist ~ Shadow Punch ~ Big Pearl ~ Light Clay.
Palkia, only used 2 ultra balls.
Entei in Colosseum. I was doing the glitch thing for infinite balls but I messed up so i decided to just throw a regular Pokeball at it and I got him :D
HeartGold FC- 3697 3834 7354
Platinum FC- 3826 2943 9809
Black FC- 2623 7586 3462
Don't mess with L!
I caught an almost max HP Ho-oh with a Poke Ball back in Gold.
It was a nice day.
I can't make signatures.
Zekrom. Full health, turn one Ultra Ball.
...Though I don't think he totally counts, since his and Resh's catch rates are intentionally higher. (Dialga and Palkia's too)
That said, I also caught Lugia (catch rate 3) last week on the first ball (Dusk Ball, maybe 7 turns, 3 Pokémon fainted in the fight. Much faster than normal for me)