What is the best location for a family vacation in western Europe?
The best location depends on individual tastes and preferences.  

For a vacation in a city, you can’t beat Paris.  There is a large range of available cuisine, from inexpensive bistros and cafes, to very expensive, Michelin starred restaurants.  It is hard to get a bad meal in Paris.  The sightseeing also is impressive, with modern architecture combined with classic structures, and many museums to fill your days. Getting around Paris is very easy, as it is a very walkable city and also has an efficient and relatively inexpensive public transportation system.  

For a lake vacation, Lake Como is wonderful, and in particular Bellagio, which is widely regarded as the prettiest village in Lake Como.  Getting to Bellagio is fairly easy, as it’s close to Milan.  The food is reasonably priced, although it’s generally northern Italian food (with limited options for other ethnic food).  Transportation around the lake is convenient with an efficient ferry service on Lake Como, although getting into the individual villages can be a bit challenging given the hills (so expect to walk!).  Many villages near Bellagio are also very quaint, and within walking distance – you’ll definitely get good exercise going from village to village.

For a seaside vacation, Dubrovnik is a great choice.  It’s not so convenient to get there from the United States, especially for those in the western United States since there are no direct flights.  However, it’s well worth the trip.  This walled city is jaw dropping beautiful.  The people are among the friendliest in Europe.  The food is fairly inexpensive and delicious, with a lot of seafood options.  And some restaurants are literally perched off of a cliff, so the views are incredible. Croatian dried lemons and oranges are fantastic, and a specialty of the region.  There also is beautiful pottery.