The best seaside town in Spain?

Hi, I am a college student looking to live in Spain this summer. I'm trying to decide where... All I know is I must live on the beach, preferably towards the south of the country. I was thinking about Ibiza, however, I don't know if it's better to live on the mainland and just visit Ibiza...I love to party but I also want to be able to travel a bit and see other places...Any thoughts?