A player of D&D games for a good number of years, only recently having discovered Roll20 and slowly getting my feet wet in it. I prefer D&D5E above most else, and also have many of the books for it on my computer for easy access, but with enough advanced notice could also enjoy a game of D&D3.5ed, Pathfinder, or Shadowrun.
I will play on square boards as a PC, but any and all games I've ever DMed have and will be on Hex - in my opinion, the majority of the story can be played out just talking to people, and the board only becomes absolutely necessary for battle scenarios, which Hex Boards just do so much better. I've been known to piss off some GMs with how in-depth I can get into the story/scenario, looking in every corner of their maps. In other words, I am the one that will tame the Dragon and attempt to make it a mount, by seduction if neccessary.
My preferred communication tool is Roll20 integrated, though if everyone else prefers it I can use TeamSpeak. I will not use Skype or Mumble, I think they're shit, and Discord is even worse with their privacy issues and the batshit crazy developers who do as they damn well please and refuse to listen to reason.