There's an article at Next-Gen looking at the history of price cuts on consoles:
http://www.next-gen.biz/index.php?option=com_content&task=view&id=5883&Itemid=2
Some quotes:
http://www.next-gen.biz/index.php?option=com_content&task=view&id=5883&Itemid=2
Some quotes:
With the Xbox 360 is nearing its 19th month on the market, it will soon have held its launch price longer than the PlayStation 2. Both launched first in their respective generations and held the line on pricing for a year longer than the competitors. The Xbox 360 would have to drop by a third in price when it does drop to stay in keeping with last generation's trends. If such a drop were to take place, the Xbox 360 Core would drop to $200, the Premium to $267, and the Elite to $320.
[...]
A PlayStation 3 or Wii price drop in the near term would align nicely with the pricing of the Xbox and GameCube in 2002. However, should Sony opt to reduce the price of the PlayStation 3, it will be likely be in the 16-20% range, not the 25-33% range that Microsoft and Nintendo chose for their last generation consoles.