A $50 Xbox 360 price cut wouldn't be as dramatic as the $100 discount Sony applied to its 60GB PlayStation 3. That discount wasn't really a price cut, though. Sony is phasing out its current $499 PlayStation 3 offerings and hasn't announced new models to fill in at the lower price point. Once stocks of 60GB PlayStation 3 consoles run dry, Sony will be left with a single model at $599.
Update — It looks like the $50 price cut will be exclusive to Premium Xbox 360 models. The Core system will apparently receive a $20 discount, with Elite systems seeing a $30 price drop.