I would agree, number 5 is the most interesting of the group.
It's well composed, with long sweeping curves rolling up from left to right. These draw the eye into the fog, and then the eye circles back down to camera left and starts over again. Nice energy.
I like your use of foreground rocks to add depth, and inclusion of the "three pillars" camera left adds an air of fantasy, almost "Lord of the Rings" to the image.
Good depth of field, probably needs to have a bit of vignette burned in. You also might consider burning in the three pillars just a bit, they fade in the fog and they are such an irresistible anchor for that side....
David SaffirGuruShots Photo Critique