Personally, I would expect Sony and Microsoft to release a system with a GPU which performed in a similar range to the Radeon HD7750 or HD7770.
As much as a GPU that is more in line with the HD 7970 would match what they did last generation, I'm not convinced either company wants to duplicate their strategy. There previous approach increased the price of their systems, lost them substantial money, it lowered the reliability of the XBox 360, and it cost Sony the bulk of their existing userbase.