What do you think of technology creating realistic living beings and objects with CGI in movies to the point where you can't tell real from fake?

From the release of Avatar, where James Cameron has created the most realistic looking CGI yet, we now have the ability to create even more realistic things on film. As we move even further down the road of CGI and its technology to create life-like effects and objects on the big screen, what do you think of it coming to the point where we literally won’t be able to tell the difference between the two?

How will this effect your opinion of the movie? What do you think of not being able to tell if what you are watching is a real human being or not? What effect could this have on society? Do you think film makers will use this as a way to trick you? What if it could virtually replace actors and actresses? Will it be a good thing or bad thing in the movie industry?

Do you think this technology will have a limit? What are its possibilities?