Tyranitar and Dragonite are tied for best Attack, with six other pokémon tied for a very close third place. It's a competitive area.
For Special Attack, there's no beating Mewtwo. Alakazam takes second place.
Shuckle doesn't just have the best Defense, it also has the best Special Defense. Ho-Oh and Lugia are tied at a very distant second. Don't forget, though, that Shuckle's HP is atrocious, so set-damage moves like Seismic Toss or Sonicboom can bring it down.
Electrode outraces all other pokémon in the Speed Category.