I'd be shocked if ALL the next gen consoles didn't have cameras and motion-tracking built-in. It's an idea whose time has come, and just not point in looking back. That said, I don't think we'll really see the full potential until they can do accurate or "good enough" eye tracking. Once they hit that plateau, a lot of possibilities open up that hearken back to the old "virtual reality" ideas, and the 3D possibilities are mind-blowing. Imagine if it could actually track the lens in your eye and know what you're focusing on. Then that object could appear sharp, whereas everything else would be blurry (like depth of field effects). I don't think people can imagine how revolutionary that would be, not just for games, but for any kind of video display.

Just knowing where someone was looking would be great info for developers (as well as advertisers!). You could track what doesn't get looked at much and put secrets there...Or perhaps reward people for spotting things near their "blind spots," such as the movement of a sniper.