Making the rounds: Scientists have discovered evidence that Homo habilis and Homo erectus lived side-by side for perhaps as long as half a million years. If the evidence holds, it will neatly eliminate H. habilis as the earliest of our ancestors, and trigger a hunt for the "true" common ancestor, which may have lived 2-3 million years ago.
However, none of this is set in stone (as it were), and there's a chance the interpretation may be overturned. What's not widely understood is our ancient ancestors were quite rare on the savannah, and their fossils even more so. Most of these interpretations are based on extremely fragmentary and sparse evidence, sometimes (as seems to be the case here) just a few individuals represented by just teeth or jaws.