The Doctor is the most consistently good character in the show, but I think that all characters have great episodes.
I think Chakotay could have been amazing had he not been saddled with the mysticism. Robert Beltran is an extremely charismatic guy.
Harry Kim has one good episode and its the one where he destroys Voyager and has to send a message back in time to avoid his own original fuck up. Its also another episode where The Doctor carries things.