I've read that it's not the quality of your camera, but the quality of the lighting that make pictures really good. That is probably not always true, though - there are many crappy cameras out there. ;-)
However, on my search to take better photos, I've read that one should invest in a good flash, and a flash bracket. In other words, the flash should not just sit on top of the camera.
Why is it so important to move the flash away from the camera?
There are also brackets (like the Stroboframe Quick Flip 350), which keeps the flash over the lens. Most seem to position the flash on the side - is it better to keep it over the lens? And in this case, what is the difference between this and mounting it on the camera?