"Leakey believed that habilis was a direct human ancestor, with erectus out of the picture. While H. habilis is a generally accepted species, they opinion that it was a direct human ancestor seems to be in question. There are now at least two species of early Homo (whether habilis and rudolfensis or an undescribed species) living prior to 2.0 myr. In addition, H. erectus (which is almost universally accepted as a direct human ancestor) continues to be pushed further back into the paleontological record, making it possible that it is the first Homo ancestor of modern humans.

"Other problems include that some people see KNM-ER 1813 as a near perfect erectus, except for its small brain and size. It could be an erectus that was at the small scale of a wide variation of traits, or it may belong to ergaster, which some believe to be the ancestor of erectus. The questions are far from solved, and new specimens are needed. Homo habilis may be a direct human ancestor, a dead-end side-branch that leads nowhere, an invalid species whose designated examples belong in other species, or Wolpoff may be right, and all these species are basically part of one highly variable widespread species." –C. David Kreger

http://www.archaeologyinfo.com/homohabilis.htm