iSight is NOT the on board camera.
Therefore, I don't ever see a time when an Apple display (freestanding or attached to a computer) will not have a camera.
Isight has been rebranded as FaceTime and upgraded to 720P HD hardware in new macs from the 24th forward. So, to answer your question... We can anticipate a new FaceTime camera built into the new iMacs.
OMFREAKINGG, that looks AWESOME, too bad I'm stuggling with funds at the moment but I hope to get one NEXT year. Gives the imac room for improvement (if any, I was sold at the Why Pc to Mac page on Apple's site a while back).