FFIV - Rydia
FFVI - Setzer
FFVII - Sephiroth
FFVIII - Squall/Zell - too hard to pick. Both are my favourites from the entire series.
FFIX - Quina
FFX - Lulu/Auron
FFXII - Basch
FFXIII - Sazh
FFXIV - Y'shtola