I agree with Killerah.
Not to mention that if you are judging every last one of your communications on the basis of "how is this going to get others to receive Christ" you have pretty much killed any chance of showing love to unbelievers.
Here's what I mean:
My LOB teammates are unbelievers. Some of them were made to attend church as a child, but never saw the point, some of them are agnostics, and some are simply unconcerned with religion at all. But all of them have already decided on their own terms not to receive Christ.
Would I like to see them saved? I very much would. But I'm not going to get them to reconsider their decision by (1), objecting when they swear and therefore holding them to a standard to which they haven't agreed, and (2), only telling them about Jesus over and over, and how they should be saved.
The first comes off as judgmental, and the second keeps me from establishing a real friendship with these people and showing the love of God to them. My teammates know that if they want advice on religion, they can always ask me. But I'm not going to bring the subject up repeatedly and beat them over the head with it while they're trying to engage in what is, after all, a recreational activity.
Francis of Assisi put it best: Preach the gospel always; when necessary, use words.
EDIT: to respond to HCS's post which was made while I was writing this one...
I think that, irrespective of religion at all, cursing has no place in a professional environment. However, the scenario you mentioned is a good way to illustrate my point. Do you think that her coworkers have changed their speaking habits? I doubt it. What they do now is make a conscious effort to avoid certain words when she's around, which makes them self-conscious and uncomfortable around her. Communication has just been made more difficult.
Now, with my teammates (I keep going back to them since they are the best example I have of personal communication with unbelievers), I don't swear. Everyone else does, but simply because I eschew vulgarities, either totally or in favor of their euphemisms ("dang," etc), I have made them conscious of the fact that their speech doesn't have to be that vulgar, but I have done it without condemning them for following a different system. On one occasion, $arge commented, "I wish we could all be like Landslide. Every time we lose a round, we're all yelling long, involved strings of cusses, and Landslide's over here just saying, 'Well, darn.'"
But to each his own viewpoint. If others' cursing bothers you enough that you feel the need to request that they desist, then certainly do so. Communication is a two-way process, and though we may be required to give up more ground because we adhere to a stricter standard, certainly most people don't want to make you uncomfortable either.