As Annie says, it really depends on what you are looking for ...
Germany is always a winner for atmoshpere, especially in the run up to Christmas with all their Markets.
For snow & skiing, then you are looking to the counties with a foot in the Alps or Dolomites.
For sunshine, you are down in the Med
For the Northern Lights you are heading up North to Norway, Sweden
etc. and if you are lucky parts of Scotland. btw next year is supposed to be the most active for a long time.
Then of course if you are thinking of staying over the New Year, it had to be Edinburgh or the amazing firework display in Madeira.
So many places, so little spare cash