Generally, none...though not always. I stock some Troegs and Omegang currently, and have a fondness for Belgian brews, personally. Chimay, in particularly, is my passion (Trappist monks) Guinness, naturally, is always a pleasure. Once in a while, I might imbibe Sake on a special occassion. But at most, I will have a single beer or a few drinks of sake. On rare occasions, we might take a shot of Glenfiddich or the wife might consume some concoction featuring Bailey's.
Of my group, only four drink. Of those four, only myself and another drink with any frequency (which is low). Beyond this, our games are traditionally late night on a Friday or a Saturday, when folks don't need something that can make them tired. Further, most of them drive anywhere from 10 minutes to 45 minutes to attend the game.
Drinking just isn't something that generally happens during our games. Not due to any moral choice, but simply practical reasons.