An amateur special effects creator going by The Faking Hoaxer on YouTube has been uploading some seriously realistic videos of events such as UFO visits and the destruction of the Space Shuttle. They're pretty amazing.
Any event powerful enough to do that sort of damage to the shuttle would not leave a cloud of debris rotating nearly in unison (and most not rotating at all) in parallel orbits of such close proximity. The debris would have been forced in all directions and would be thousands of miles away "three days later".
Don't get me wrong. It's great looking CGI and all, but it's just not physically possible and so that makes it look even more fake to me. :-)