If you have the time and money for it, you should leave the city of Valencia and see more of Spain. The Balearics, Barcelona, Madrid and Sevilla for example are all worth paying a visit.
You could choose to plan your short trip out off Valencia by yourself or you could choose to go to a travel agency and let them plan the best route for you. There are about 285 travel agencies in Valencia. Most of them offer their own special discounts for popular destinations in Spain so look around and see where you can find the best deal.