You can bring in a reasonable amount of wine for your own consumption (and in most situations a case of wine is considered a reasonable amount). However, each person can only bring in 2 liters of wine and 2 liters of "fortified wine" duty free. Any amount over that is subject to customs duty so if you bring in a full case you should expect to pay some duty. Sometimes you get lucky and the customs agents will let it "pass" without collecting the duty but don't count on it.