I figured Austria might as well host it, seeing as he loves throwing them and the New Years Ball is the most prestigious one of the over 200 balls he hosts a year. (And yes, I am aware of the wordplay xD)
It takes place in the Hofburg, a palace right in the center of his capital Vienna. There are many different halls it takes place in, but this is how a dining area would look:
and the dancefloor:
I hope this is alright with everyone, and I hope enough people will show up to have a fun time. x3