Heres my take on the near future:
Next few weeks are gonna be real interesting. The weekly sales indicate that the Xbox weekly lead over the PS3 has shrunk to less then 10k. Theres a very good possibility that the PS3 might be able to break the Xbox's 20 week streak. If the Xbox can maintain its shrinking lead for another week or two, Fable and Kinect will launch within a week of each other so I reckon the Xbox can will keep its streak going. If Gran Turismo launches very shortly after the Kinect (theres rumours that the delay will only be several days), theres the possibility that the GT5 sales will not match the Kinect boost. (Halo Reach's opening week boost was around 100k and i have reason to believe GT5 may have trouble boosting even that in its debut week). However if Gran Turismo 5 launches a few weeks afterwards when the Kinect boost has worn off, it will almost certainly break this current Xbox streak.