I found this list of the best 50 singers/groups of Spanish music. Many groups from the 80s (goodness, that styling!) but a good list for those interested in the "classics". Personal favourite is ´A quién le importa´ from Alaska y Dinarama, it is still used nowadays to say I don´t care what you think of me and she (the singer, Alaska) is considered a symbol in the gay community in Spain.
I hope you enjoy!