I guess for me, I picked my battles, so to speak. I learned to "know when to hold 'em, know when to fold, know when to walk away and know when to run." There were times when the verbal banter was quite mild. Limited to some off-colored jokes that I didn't find amusing, at all. Those were times when I definetely spoke up and let it be know that I would not tolerate being spoken to in that manner. Like elizabeth1979 said, "I will leave if you call me names." Clearly defined my boundary, and then I enforced it. The next time he called me names, I left.
When he got argumentative (after a beer or two), I opted for the "You may be right." Something to end the conversation so that it didn't get into a tit for tat.
When he was full on drunk, and full of guilt for his behavior... and looking to put some shame on me to make himself feel better... I walked away completely. I didn't want to be around him and accidentally slip and say something awful. I didn't want to give him any reason to blame me or include me in his drama.
There are right times and wrong times to have discussions. Intoxication is NEVER a time to try and reason things out... nor is anger.