It really depends on what you are looking for. I think that both Barcelona and Madrid are great. Barcelona is very rich in cultural history and full of beautiful architecture. It also has a great city life. Madrid is more metropolitan and international. If you are looking for the best weather in Spain, all year around, I would recommend either Malaga or Marbella, in Costa Del Sol. There you would be able to have the best of both worlds, being both close to a big city, as well as a beautiful vacation destination. Marbella is full of great night life for the young with some of the best nightclubs and restaurants in Europe. Malaga is a beautiful port city, and also rich in it's history. Another great thing about Costa Del Sol, is that you are just hours away from Northern Africa, by boat!