I don't mind having a bit of beer or wine with lunch when my coworkers and I go out. I wouldn't have more than that though, because I tend to get sleepy when I process alcohol so I'd be pretty unproductive for that afternoon.
I would not open a beer while actually AT work. I think most companies would feel that was inappropriate, although I've heard that they're more liberal about this in Europe.
Having said that, my previous company used to have a thing where every Friday at 4:00pm you'd go upstairs to the one conference room where they'd serve beer and various snacks. I miss that