Yes, the name "New Thought" is actually a bit silly because there was nothing new about it all....as you said if you go back to the Bible you'll find verses like "As a man thinketh in his heart so is he", the teachings of Jesus on having faith the size of a Mustard seed being able to move mountains etc. If you go back even further you'll find it in the Hermetica - the notion that mind/thought is causative. So this ancient principle has long been out in the open - the New Thought movement was just simply the vehicle that commercialized it and made it accessible to the public. Since then there's been no shortage of material, with "The Secret" being the biggest book/movie that has stemmed from New Thought. I didn't read the book but did see the video - it was okay. I felt it left some things out, for example it's not enough to just think of 1 million dollars. You can do that until the cows come home, it won't do anything for you, especially when deep down you most likely don't believe you deserve that million dollars. And that's the thing...your desire must be congruent with your belief in having it....many people desire x but very few from what I have seen feel they can have or deserve it, whatever it may be. Of course I am talking about "lofty" things here...most people are taught to believe they can't, or aren't good enough, or any other such thing.
I'm of the camp that believes in it. I've used it towards very specific things and its proven itself to my satisfaction...when I've mentioned it to the other people, the skeptics have said "It would've happened anyway". It happens again, "Well it would've happened anyway". You could do it 1000x and it's always "It would've anyway, so do it once more". Now could it have just simply happened anyway? Sure, I wouldn't rule it out. They could have just simply been "coincidences"....however when I think of a couple very specific times in which it has happened....to me it doesn't feel like just a coincidence and I highly doubt it would've *just happened*.
At the end of the day people will either believe in it or not. If they don't, perfectly alright, but you owe it to yourself to test it. You have to test it and not just give it lip service. A lot of people say "oh yeah I believe in it, law of attraction, imagining creates reality" but if they are perfectly honest....i'd wager they think about how they can't, the different kinds of doubts they have...basically their mind is consumed with what they don't want the majority of the time. So do put it to the test and set the bar high - it's important to pick things that aren't *impossible* but appear difficult so when it does occur, you can't just dismiss it as chance. If you do that, and it happens, and then you try it again and it proves itself again, and this happens over and over....what then does it matter what the world thinks?
For those of you who are into this kind of stuff I suggest you check out Neville Goddard. He is very similar to Joseph Murphy which some of you have probably heard of- He is my favorite lecturer/writer on this subject & I do feel he is the best (And that is not just my opinion). You'll find a lot of actual live lectures on youtube. He was active back in the 1940's until the early 1970s.