For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
I think some people, when they think of 'bar', imagine a seedy sort of night club where people go to get sloshed. However, many bars are actually in restaurants, and quite a number of them tend to be social hubs centered around sports or just a casual place to meet. Drink, in scripture, seems to be allowed for social functions (like Weddings or festivals of the Lord), - but drunkenness and debauchery are condemned.
There are so many factors that would go into whether one wanted to be a bartender or not, the most important being the conviction of the Holy Spirit. It would be hard, possibly even incorrect, to make a blanket statement about it being an 'always OK' or 'never OK' issue.