Stoli is great even when you're drinking it straight. Stoli with a slice of lemon and a couple of ice cubes
GG is also very nice but more expensive.
When I was in Moscow last November, from what I saw they enjoy drinking it straight plus Stoli is one of their cheapest brands (a bottle costs 4.5$) Most of their brands don't export to other countries but I've seen Russian Standard in a couple of bars lately.