In Spain, San Sebastián, Pamplona and Zaragoza. There's also Huesca between Pamplona and Zaragoza, a very pretty small city in the Pyrenees. For Pamplona check that your visit doesn't coincide with the San Fermines (festival with bull running) in early July as you won't be able to find accommodation!
San Sebastián has three lovely beaches including one for surfing (small waves), a beautiful old town with lots of lively bars, an old fashioned square and a lovely church, an aquarium, various uphill walks with a view - of varying difficulty, a cathedral, a spa on the beach front, a couple of small museums, and absolutely cracking food from gastronomic clubs and Michelin starred restaurants to simple pintxos bars where everything looks and tastes amazing.
Pamplona is good for wine tasting (you're also not far from La Rioja, Logroño, etc.) and its local chorizo, as well as history and culture and it's a pretty city with nice parks and places to eat and drink and the people are very friendly.
Zaragoza is the old capital of the kingdom of Aragón and is basically between the desert and the mountains. The drive there from any direction is spectacular with constantly changing scenery. Eating and drinking are cheap there, the cathedral is well worth a visit.
Happy holidays!