Effen for shots, sipping, and finer mixed drinks. I tried various brands and found the wheat based vodkas like Effen were the smoothest for me.
There is a vodka from Michigan called Grand Traverse that is smooth. Don't get up there anymore.
When mixing in orange juice, 7-Up, Gatorade, lemon-aid....for golfing, at the beach. or partying, then for the money, you can't beat Burnette's. Cheap but still smooth as it's multi-filtered, plus comes in a unbreakable plastic bottle. Oh yea!