I think that the coolest thing about my iSight web-cam is it's being able to point in in any direction from it's stand. If it was built into my PowerBook, I would have to sit in one exact spot. This would work for a one-on-one business conference, but not for a family. When I video chat with my family, they can just adjust the camera side to side or whatever, and I can see the other family members, the dog, someone's new toy, whatever. If the iSight was attached to the computer, it'd be much harder.