viewfinder shot - Same exposure/iso settings http://cchanphotography.com/images/sensor_issue/viewfinder.JPG
I THINK it may be the secondary mirror stuck down - Attached to the bottom of the main mirror, which is semi-silvered, is a secondary mirror pointing down. If this is stuck down when the main mirror flips up, it will let light in from the viewfinder and possibly reflect light back in at the sensor.
set your camera to "lock mirror up for sensor cleaning" and have a look inside - the back(bottom) of the main mirror should be flat against the top of the inside.
My guess is that light is leaking in through the viewfinder. When you put the camera to your eye, it's blocked, but in live view, it's not, so some light leaks in. This wouldn't normally be so apparent (particularly not in a relatively short exposure like this, ¹⁄₈₀th of a second), I wouldn't think, so something else must be going on too, but I'd start by covering the finder in live view to see if it makes a difference.