Oh wow, difficult to say.
Picard: He was an extremely good captain, could be human without losing sight of his command, he could command without losing sight of his humanity, he was intelligent, sophisticated, wise, humble, fiercely protective, and brave.
Data: Was more human than the rest simply because he wasn't. I know, doesn't make sense, but to me it does.
Whoopie Goldberg's character: I really enjoyed every episode that she was in.
The rest, well, all just kind of fell into it. I couldn't see an episode without them though.
Cheers,