Best European City for less than 24 hour layover?
 

I am traveling with a group of women this coming December to a conference in Israel. We thought it would be fun to leave a day or so early and layover somewhere fun for a day.
With this being said....
What cities are recommended for a quickie day trip that aren't too far from the airport or too complicated to navigate after a red-eye from the east coast.
We were thinking Paris, London, Amsterdam, Zurich....

Are you airfare budget constrained? Depending on the airline (code share partner schedules) and the airport, the airfare skyrockets if you add an intentional long layover. If this is the case, you might not have as many layover options as you outlined.

Smaller city like Amsterdam might be easier to navigate.
Paris is alway fantastic..research RER to town and the map of the city.
Zurich could be cold.

Amsterdam!

Amsterdam or Paris make sense. It will most likely depend on airfare.

Amsterdam, Brussels, Copenhagen, Paris, somewhere in Germany eg Berlin/Munich, Helsinki, all these have relatively easy transfers to city centre (not sure abt Berlin though).

Paris...But have you considered Rome or Vanice?

Consider Munich. You can reach the city center easily by S-Bahn. The downtown is compact and you could go to the Christmas market , have a nice meal in the Ratskeller, and a stop in the beer hall. You could also just stroll the streets or the paths in the English Garden.
Munich is wonderful in December.

I would not stop in Paris because just one day isn't enough and it would be so sad to leave!