1

Lisbon is the cheapest, and it's not far from the beach. For surfing, the ocean is a better choice than the Mediterranean.

2

Would agree with 1, Naples is a bit dodgy, not great surf either, Barcelona is pretty expensive and too me a bit too touristy. Lisbon has great vibe especially if you know it well.

3

Just got back from 2 weeks in Northern Spain - some nice beaches along the Bay of Biscay and I did see some surf schools advertised, so I would assume there is good enough surf in places. Water temperatures are more like S. California (chilly.) I know there are surfing contests just across the border in France. San Sebastian is the 'trendiest' location, but there are many cities and towns along the coast. I rented a car and traveled a loop from Bilbao to the Pyrenees, back up along the coast through Santandar, than as far west as Leon and Ovieda with my family and always felt very safe, even in big crowds. Lots of fun tapas bars and cafes in the city centers of every town and city we visited. Not sure of the overall yearly climate - it was beautiful this last week of June. Even though the cites up north are smaller (150 - 300k), they feel bigger since they are compact.

4

If you search "San Sebastian Spain surfing' there are several discussion threads at surfing sites.

5

Nothing completely fits the bill, but I would say Naples the least.

Lisbon is the cheapest. Next to the ocean with good waves. Weather is good but can be really cold in winter.

Barcelona is good on most things, but housing is pretty expensive. Or can be - way cheaper if you share apartment like most people here. Waves completely suck though there are quite some surfers.

6

I agree with everyone else, either Barcelona or Lisbon. I think Barcelona has more of a nightlife, but Lisbon is cheaper and a lot of fun too. I'm not a fan of Napoli, but you'll like it if you're into trash and stray dogs.