what would be a "good" vodka for this recipe?

I use Grey Goose, but Stoli, Ketel One and Absolut are all good!

Chopin would also bee a good choice too I think. Because its a potato vodka, its a little smoother then grain vodka and its about the same price as Smirnoff.

Smirnoff wins in blind taste tests even over 'high end' vodkas; which you're mostly paying for the cut glass bottle there.
http://www.nytimes.com/2005/01/26/dining/26wine.html

My rule of thumb is if I won't drink it I won't cook with it.