Common family names in Spain are Martinez, Sanchez, Gonzalez, Alonso, ... Most of them has the suffix -ez, that comes from the Moorish who lived in Spain for 800 years. That suffix means "son of", thus we find that Sanchez, that is my second family name, means "son of Sancho".
On the other hand, my first family name, Riba, is not so common and is a catalan surname. It means the bank of the river. My first name, Silvia, has also a meaning related with nature and comes from Italy.
Some years ago I noticed that another girl, 5 years younger than me, was named eactly like me, the same first name and the same surnames also. It was a litle amazing and frightening too.
There aren't many names from other countries popular in Spain, but the situation is now changing with the immigration. As a result, we can find many south-american surnames like Vargas, Expósito or Ortega.
I usually use the surname with the title Mrs/Ms/mr when I'm working, at least until that person allows me to call her/him by the first name. But, when I'm with my friends I just use the first name.
Pet names in Spain are "pichurri", "cariño", "cari" ,... a little ridiculous, I have to say.