Actually, you can bring aboard wine and champaigne with no problem (it states that in Carnivals' website somewhere). As far as liquor, we bought little bottles of liquor (airport size) and stuck those in our checked bags. Don't bring any liquor in your carry on - they have x-ray machines that can detect anything. I was carrying my wine aboard in my carry-on and they x-rayed by bag and saw my bottles and yelled out "bottles, bottles!!!"
Also - there is free ice tea, coffee, apple juice and lemonade at all times. Most liquors will mix with this combination. Have fun!
When you say wine and champagne are no problem, do you mean in carry-on. We will be celebrating an anniversary and a birthday (Carnival Conquest in Sept.). I was told by someone that you can bring on champagne if that is the case. Did you understand that to be a true with the carry-on? Only the liquor is the problem, right? Felt it would be better to carry it on than to pack it. Thanks.