Depends. If you want to call localy or others from the US to call you, then Italian one is cheaper (for you).
US card would be cheaper for the US caller, but more expensive for you (but combined it would be still cheaper than option one).
You should check roaming prices for Italy with your operator.
And, if you want to call to the US, than option 1 is the cheapest, but really, rather use internet calls :) almost 6 years ago