Well, where I grew up calling something "gay" signified displeasure for it but it never insulted anyone. In fact, a few of my friends who are indeed homosexual use it quite often. I think it's meaning is determined by those who hear it rather than those who use it...
I personally have no issue with it nor do any of my friends, but if it bothers someone else, I typically avoid saying it for the sake of not hurting their feelings.