For my vodka it is Stoli - but more for tradition; don't think I've tried even a handful of others (aside from 'well drink nights' that are best forgotten). Even if it isn't traditionally aged, you will benefit from getting one that is at least a year or two old, to let the nasties filter out some. Once I graduated from HS and didn't need to hide that I was drinking, vodka lost a lot of its appeal
