Rohen, I understand your comment and have some of my own:

Although there are many dialects in spanish the most important thing is to consider what will be searched. I only know traditional spanish, but I always try to limit accent use on my site because search engine users aren't usually searching with accents. Musica for instance is a much more searched term than Música. I think its an interesting problem and one that google needs to adress; web developers shouldn't be penalized for using the correct grammatical structure but sometimes that's the case.
Otherwise its kind of just a game of give and take. Hope this helped