Conclusion: The Canon EOS-1D X is a great choice for sports shooters and photojournalists, but is likely an overkill for most shooters.
Pros: Full-frame image sensor. 14fps burst capability. 61-point autofocus system. Excellent images at very high ISO settings. Built like a tank. Loads of controls. Dual CF card slots. 1080p video capture.
Cons: Very expensive. Heavy. No built-in flash. No headphone jack. Uncompressed HDMI video output not possible. Switching between still and video live view mode is cumbersome.
Conclusion: Undoubtably Canon has moved the goalposts with this camera, as there are Canon pros, like Chippy, now considering the hefty investment in a new piece of kit. From an average enthusiast's point-of-view, this camera is certainly offering more than you really need. If we were desperate to splash some cash on a Canon we'd go for the 5D MkIII but if we had to gamble our livelihood on it, we'd pick the 1D X every time.