Oh so many, how to choose!
Cary Grant because of his suaveness and twinkle.
Katharine Hepburn because of her hautere and class with the warmth underneath.
Honorable mentions:
Joel MaCrae because he is adorable.
Jimmy Stewart for his gosh darn Americaness.
And Claudette Colbert and William Powell for Nick and Nora. (Bark, says Asta – don’t forget me!)