The Spanish Rolling Stone's list can be found here: http://rockblogazzurro.wordpress.com/2008/01/02/las-200-mejores-del-pop-rock-espanol/

From the pdf:
"The list has collect the songs considering the importance of the band, and the song impact in its time, in its country of origin and in a regional level as well. Local lists, as well as books, specialized webpages and fan forums were taken as sources; all of them with a proportional value."

That Rolling Stones list is more Spain-oriented. There are many obvious omissions when you considered the whole spectrum of the spanish-speaking world.

As for Serrat, I really don't know why he didn't make it this time, he's great. I'm from South America, and he's as important here as he is anywhere else, and that's a fact.