I love New York, but touch anything in this damn city, rub your eyes, and presto – you've got yourself a cold. I've also been observing men's hand-washing habits in restrooms. My conclusion: don't ever shake a man's hand. Ladies, I suspect you may be just as bad, but alas, I have no evidence.
My advice is to carry around one of those alcohol-based gels and use it constantly. It's better than soap. (Incidentally, if you're going to go with soap, the liquid is much more sanitary than the bar.)
And germs at the gym... you don't want to know.