Which Champions should I get?

I've been pretty torn on these decisions, so I decided to ask the public. Here are the choices:

TOP: Renekton, Wukong, or Shyvana?

SUPPORT: Blitz or Lulu?

MID: Swain, Orianna, or Azir?

ADC: Kogmaw, Graves, Ezreal, or Varus?

Difficulty doesn't really matter. Any sort of input helps. You can answer one or many. Thanks for the input!