From a very cynical perspective, religion is nothing more than the ultimate fit-all-scenario justification.
I have no problem with religion on the individual level - believe whatever you want to believe as long as you don't impose your beliefs on me. But organized religion is frightening in what it can accomplish.
In an uncivilized society, I think it is definitely necessary as a means of social control (e.g. morality).
In a civilized society... I can understand the basic intrinsic desire for religion deep within, but in a way it is also a hindrance to the growth of our society, particularly the worldwide society. Many religious people seem to be too focused on the division between different humans rather than the overarching ties that bind us. Most of them are good-hearted or good-intentioned, but completely insular. After all, religion at its core is all about dividing the world into US and THEM, the good and the bad, the righteous and the evil, the ones who make it to heaven and the ones who don't. Maybe that's just human nature too, but religion hardly breaks that pattern. Sure, religion can bring people together, but only when you believe what everyone else believes, not before. And that's not really "bringing people together," not really.
Personally, I think that religion is just fine for individuals. If anything should be banned, it should be the organized religion structure, which even since its beginnings has always been nothing more than another power play.
Wow, I sound like a conspiracy theorist when I say that.