Costco sells a few different Italian olive oils. The best flavor is the Toscano or Val di Mazara. (Which one they have varies from year to year.) They only have these for a while from late spring until they runs out, and it is the most recent October/November harvest. They are in tall square green bottles, perhaps similar to the Spanish you mention.

Yes, I should have been more specific. Out of the two italian olive oils in tall bottles, the one with the purple colors tasted bad to me. I think it says Italy on it in big letters. The green label bottle, also from Italy but which says Toscano, tasted just fine (though I still prefer the Spanish bottle).