Hi Erick, I am in the United States and schools and college/universities here often teach "neutral Latin American Spanish" that is somewhat slowed down for students. It sounds something like this ---> https://soundcloud.com/djxspth/neutral-latin-american-spanish-accent-taught-in-us-schools I know almost no one speaks like that in real life but I like accents that sounds similar to that -- namely, Guatemalan, Mexican (without regionalisms and sing-songy intonation), Bolivian, Peruvian and Colombia (the latter two, also without sing-songy intonation). Hope that answers your question. :)

I don't think there is a standard spanish accent, each country has a different one though. Even in Mexico it depends on where you live. North, south and center people, the accent they have is different. If I choose one, it'd be the accent of people at the center of people in Mexico (people usually said we speak “like singing") because we can do many accents without problem, and people who has an accent can't do it.

I appreciate them all and love the diversity within the Spanish language but Argentine and Puerto Rican are my favorites..Colombian is also very nice.