Like Blu-Ray, for example.
It’s all still rumours, of course, but we think that’s only because developers haven’t got the balls to say it.

Sony were ridiculed at first for the extra expense caused by the inclusion of Blu-Ray, but games are now starting to require the extra space, which can be as much as 50GB on a dual-layered disk compared to the 9GB on a DVD as used by the 360.
Resistance, a PS3 launch game, used 18GB, Lair is set to use 2GB per level, and now GTA IV, this year’s biggest game (in the absence of Killzone 2 and MGS4) is looking more and more likely to be hamstrung by the lowest common denominator – the DVD.

One day there’ll be an official PR about this, and we can all just go back to bed.