Aesthetically? Rhyperior easily. He looks like he was drawn by a drunk four-year-old.
In terms of necessity? Dusknoir. None of its stats really improved that much at all, and Dusclops is already a solid wall. There are at least 100 Pokemon that would have benefited from an evolution more than Dusclops did.
Ist zwivel herzen nachgebur, daz muoz der sele werden sur. - Wolfram von Eschenbach
This one was my pick for best Fighting Type on a "Best and Worst Pokémon by Type" list I did. With good typing that made it only weak against Flying and Ghost types and a bunch of critical hitting moves in its movepool, this was a great attacker and a great addition to any team.
WORST - Magnezone
This one, while not completely bad, was still a disappointment. It didn't really improve all that much from Magneton and didn't really get any additional attacks. It was as if all they did was give Magneton a new look and that was it. I would have loved to have seen a better movepool or even the addition of the Levitate ability
The fourth wall has shattered... Heroes of Arcadia - http://www.fanfiction.net/~anthonybault