P.S. I just had to come back to see how you were doing! Having had native speakers from different countries, this is most interesting to me! I remember one year with a girl from la Argentina, a boy from Spain (las Provincias Vascongadas) and another boy from Puerto Rico in the same class and when the rest of my students couldn't understand why they couldn't understand each other!
Some other examples that come to mind:
cake: torta, biscocho (Caribbean), but it's a "roll" in Latin America and queque from Central America.
boy: chico, muchacho, mozo, compadre (more like slang), even vato (Chicano)
corner store: el chino (Panama), el colmado (Caribbean), la bodega (Cuba) la pulperia (Nicaragua)
soda = gaseosa (el Perú), refresco (Dominican Republic but in el Perú "refresco" is a sweetened drink or punch. (and even "el ponche" from some Chicanos)
blond(e): rubio (-a)(Spain), blondo (-a), fulo (Panamá), huero (-a), (México)
pig = puerco, cedo, cochino
peach - melocotón, durazno
avocado = aguacate (México), paldad (SA), even "avocado"
kite = papalote (México), barrilete (la Argentina), cometa
When it comes to the "ultimate authority" it is, of course, La Real Academia Española.
Sra