nightlife

So Im planning a solo trip to Spain this summer and was hoping to hit some beaches. Ive heard Spain has a lot of them. I was curious what the best beaches to visit as a solo backpacker would be.

Ive heard Ibiza is great, but really only good for groups of people. San Sebastian is supposedly nice but doesnt have to much going on, and the Andalucia Region in Southern Spain is supposedly pretty nice.

Im looking to swim, surf and do water sports during the day, and would like to go out and meet new people and have a good time at night.

Any help you guys got would go a long way.

Hey! Me and one or two of my friends are planning a Euro trip to take place probably next May (2012). We want to go to the places with with best nightlife, beautiful beaches, inexpensive (for the most part), and safe. We will have about 5000$ (CAN) each and want to go for about a month.
We will for sure be going to Amsterdam (starting there) and Barcelona. Possibly going to Berlin, Cinqueterre, Florence, Ios, Croatia. Thoughts? Best cities/ places to stay away from? Must see cities for two 18 year olds looking for adventure?
Also would you recommend staying in hostels?

I see on a lot of the forums that their are certain clubs with dress codes. I plan on going to a lot of clubs while I’m in Europe, and I want to look good while I’m there. I don’t wanna pack too much though, so what is the best club attire that won’t take up too much space in my bag?