What is your favorite brand of vodka? I have always been a fan of Tito's.
Tito's ...Is what I keep for vodka drinkers as it's gluten free and it's good stuff. Grey Goose is over priced/over rated. If you're mixing it in cocktails get the cheapest as it doesn't matter.
However I'm a straight Bourbon drinker. I can even do whiskys and blends if Crown is all that's around.
I was never much of a vodka drinker, but when I was working at the club, I always preferred Grey Goose or Belvedere.