I say Ice because it beats dragon and almost everyone has a dragon in [their] team.
It's funny because I rarely have an Ice or Dragon Pokémon in my team. I always have Fire, Grass, Water, Electric and Flying; no matter the game. After that it really depends on who I catch first and decide to keep. I often but not always have Fighting, Normal (usually paired with Flying), Bug, Rock, Ground and Psychic. Despite being my favorite type, I rarely have a Dark Pokémon in my team. I tend to keep mostly Pokémon I caught earlier in the game.