[DISCUSSION] "Best" Competitive type

[moo311]

My next monthly giveaway looks like it's going to be strongest of a type. I was thinking of doing strongest of each stat for a type (Highest HP water type, highest attack water type, highest defense water type, etc.) and I was wondering which type I should do. Which type is the "most competitively viable"?

Normal:
Fighting:
Flying:
Poison:
Ground: 6
Rock:
Bug:
Ghost:
Steel: 4
Fire:
Water:
Grass:
Electric:
Psychic:
Dragon: 3
Dark:
Fairy: 2