Killzone and Infamous typically sell in the 2 million range. Could that change this generation? They are both rumoured to be launch titles and will likely be marketed pretty heavily since they could be the only big exclusives for launch (most other big launch games will likely also be on PS3, 360, 720, PC). I think its likely these 2 will join Kratos and Nathan Drake in the 5+ million club.
When the herd loses its way, the shepard must kill the bull that leads them astray.