HP Fire because it hits many important things, such as Forretress, Scizor, Skarmory, and more.
HP Ice only really hits like Dragonite or Gliscor, while Nite has multiscale, and Forry/Sciz/Skarmory are more important. It also depends on your weather, or what your team needs more.
All these questions you give me depends on the team. :<