It's Donald for me. He's an incredibly versatile character who is, in my opinion, the foundation of the Duck universe. Scrooge is a great character as rich in his depth and entertainment value as the character purports to be in-universe, but there's just something about Donald. He's so easy for us to insert ourselves into, while also being a great character on his own. He can be a jealous villain, a bold hero, or a cowardly fool, but he's always Donald.