The Dragon type is often considered the strongest type due to the fact that it only has three weaknesses (ice, dragon, and fairy) and can learn all the 17 elemental types. 4 of the pseudo legendary Pokemon are also Dragon types and after Arceus the Pokemon with the highest base total: 700 is Black/white kyurem which is a dragon type. Dragon types usually have great offensive power both specially and physically
More than likely, it's Dragon.
But, now that Dragons are weak against Fairy-types now... it evens up the score. :P