Spain was one of the first countries to legalise gay marriage and yes we mean marriage not civil partnership. The one drawback is that one of the happy couple must have been resident in Spain for over two years. So if your thinking about popping over and getting married on the beach, forget it.
Spain is a very regional country and similar to the USA, still has local laws set by regional government. This does mean that regions in Spain can be very different. The main holiday destinations are all fairly similar and it is here that you find the main groups of foreign residents.
Most people are surprised to discover that Spain no longer has a state religion. It is still a predominantly Catholic country but the government has recently stood up to the Vatican on a number of issues.
Although most of Spain is fairly all accepting, including of the Gay way of life, it is still not something that is generally flaunted in public. Such restraint is more respectful, especially to the older population, who have seen such dramatic changes in their country. It is very noticeable that in some regions, Spanish run gay bars do not have any windows.
Spain does not have a public nudity law. However this does not mean that people just walk around in their birthday suit, but in the relevant areas, like the multiple nudist beaches, a certain level of freedom is accepted.
Spain loves a party, and you will find many more public holidays than you are used to back home. Lots of parades, bonfires, fireworks and drinking. On some of the public holidays it is even illegal to work.
Spaniards accept the fact that a large proportion of their economy is reliant on tourism and a local foreign population. However they do appreciate it if you respect their local customs and even join in, maybe even learn a little Spanish.