The website describes a weight concept limit (one bag 20 kg) and a piece concept limit (max of 2 bags 23 kg each). I am a little confused about which choice we would qualify for. We are flying economy from the USA to Rome and back. My husband and I will each have a suitcase for checking in and each a small carry-on bag. Can we do the piece concept choice so we could have a little more weight per checked luggage (maybe room for things we buy there!)?

My brain is in overload so any help with understanding this will be greatly appreciated.

It isn't a choice, the piece concept applies to some destinations and the weight concept to others. Flights to or from the US follow the piece concept, so you get the higher allowance.

FWIW, enjoy it while you can, I predict that most airlines will switch to a 20kg (maybe 23kg, i.e. 50 lbs) for virtually all destinations within the next year. Already, Delta, Continental, and US Airways (at a minimum) have dropped the limit to 1 bag at 50 lbs for trans-Atlantic travel. Moreover, every European and Asian carrier I have seen already have a 20/23kg limit for flights to most non-Americas destinations.

tg - after reading your comment I went to the Continental site and saw the $45/$50 charge for the second checked bag for international travel. This note was not there a few days ago when I checked for baggage restrictions/charges.

Delta has been charging $50 for quite awhile on flights to Europe.

My SIL called Alitalia and was told that we are allowed two 23 kg bags per person for checking as you mentioned, travelgourmet. I can't imagine lugging that much with us so we are all just taking one bag each and she will check her carry-on bag also.