I usually tend to like weather teams, based on Sandstorm, Rain, or Sunlight. I dont like hail because there's only one pokemon who can make it automatically, and its not really worth putting on other guys. SS has two great pokemon, Tyranitar and Hippowdon, and Rain Dance has Swift Swim, Rain Dish, and Thunder. Sunny day has Clorophyl, Solarbeam, and Fire Attacks. SS also gives you rock pokemon a boost against Ice Beam. I'm currently making a Rain team. So if you want to go weather, here is a list of pokemon that you might consider:
Sand Storm:
Skarmory
TTar
Hippowdon
Areodactyl
Fortress
Scizor
Registeel
Rain Dance:
Kingdra (Swift Swim)
Kyogre (Ubers)
Kabutops (Swift Swim)
Suicune
Milotic
Ludiclio (Rain Dish)
Almost any water type
Raikou
Almost anything that can learn Thunder
Sunny Day:
Groudon (Ubers)
Infernape
Any strong fire
anything that can learn Solarbeam
Executor
Tangagrowth
There are many more UU Clorophyls if you want them.