While reading UFO Magazine today, one of the articles was talking about a book about this new agey guy who thinks that "star beings" are going to help us develop telepathy in order for us to move to a new spiritual level. In one sense, it's a cool idea, but then I tried to think about what the advantage would be to telepathy.
We humans prefer to think of ourselves as individuals, albeit social individuals and for the most part it works. Sure we can be selfish, but we value our privacy from time to time, and for the creative types that can be crucial. If we suddenly found ourselves with telepathy however, our minds would be open to anyone (or anything) close enough to us to hear thoughts. Unless there was a means to block people from reading our brains or we started thinking the same, I doubt we'd be able to walk down the street without hearing stuff we don't want to, or don't need to hear. Heck, there is enough of that without the telepathy.
From an evolutionary perspective, I see almost no reason for telepathy to develop. There are some situations where perhaps a species could develop something similar, such pack predators who rely on silence, but still need to communicate, but I feel it is unlikely that it would. Also like this article from Hard SF mentions, if a species already has other means of communication, the development of telepathy is doubtful and having multiple means of communication ourselves (vocal or visual) I find it unlikely we'd develop telepathy to replace any of them.
Overall I feel the idea is fantasy more then anything, at least for Earth based life. I will admit that it could develop elsewhere as a form of communication, maybe even in aliens who might be visiting our planet. And while I do feel that we as people need to evolve more spiritually or philosophically, I don't see how telepathy would help, in fact it would probably do more harm then good.