Although I don’t drink alcohol, I am not averse to socialising in a pub from time to time, especially now that smoking in enclosed public places is illegal. However, you naturally expect a few raised eyebrows when you order something non-alcoholic, if not outright peer pressure to go for something inebriating.
Surprisingly, I find that almost nobody ever bats an eyelid, and I suspect that it’s because I always order a Diet Coke. It helps if you insist on Diet Coke rather than normal Coke, with ice cubes and a slice of lemon: the embellishments have a somewhat distracting effect that makes it easier to overlook the fact that none of them contain C2H5OH.
On the other hand, I don’t recommend orange juice, unless you want to draw attention to the fact that you intend to remain sober for the entire evening. In situations like that, it makes you look like a stereotype.