I've got respect for Cray for having such an idealistically heroic background, which compels him to confront Plasma various times, but he's at the lowest tier.
Faulkner is quite formidable w/ Mudshot, the accuracy-lowering technique, making him famous for just that. Never disrespect anyone who can throw your strategy in a serious state. Sabrina has her moments, just a tad of a fascination with psychic/energy-type power.
Speaking of energy, Misty is effective at being an energy fighter w/ Bubblebeam + Recover. She has a strong role in the anime as well, so, as a fan of the early seasons, I'll let her occupy the top of my favs.
Guess who outlined himself as a key player, for he has a strong affinity w/ his pokemon, Vulpix in particular. Those who have seen the early episodes will understand, perhaps. He also has an honour-type parsonality, and strong affection, especially for the Joys/Jennys. :P As the character who has the most dimension and substance, along with his awesomely-strong team, Brock owns the top spot.