Great Topic. Here is my opinion, if you can drink and moderation, still participate as normal in the game, then it is not a problem. If your drinking is making others uncomfortable, or others not enjoy the game, then it needs to go.
Here are some other tips:
Drink the night before, alot, so much that you won't want to drink on game night.
Consider another night of the week, every so often, to get together and chat, drink, play board games.
Set a house rule: No drinking during the game.
Start 2 hours earlier, at the end of the game, pull out the beers! (Or whatever you like to drink).
I tried drinking during the games but I couldn't follow what was going on. I am a big drinker though, so it wasn't uncommon for me to drink 12-20 beers during a 7 hour game. Also, I over did it one time, passed out at the table, and scared off a possible new gamer/player.
I have been a sober gamer ever since. We play on Saturday from 5 - 12. I make sure to get all of my drinking out of my system on Friday.
Lastly I will say that you are partly to blame for your friends DUI. If you don't feel a little responsible, you should. If he would have hit somone, and hurt them, you could have been charged. From now on I suggest that you tell your players that if they drink during the game, then they
must do it in moderation (1 to 2 beers an hour depending on weight). Or you will have to end the game earlier and make them sober up. Or you may suggest telling them no drinking at all. Not just for themselves, but for the consideration of others.
Just my opinions there

. I'm usually under the assumption that, if you are drinking, you are an adult, and thus need to act so when it comes to driving. If you think you have had to much. Just wait a while or sleep over. I can remember many nights that my DM let me drive home (or other friend at other party) and I should not even have had the keys. Some people, like myself, just need parenting. Kinda sad really.