It was a toss up almost for me between number 5 and number 7.
Number 7 won out. No people, and it gives that feel of a clean beach and being the first person on Earth to catch that view. No one there to share their thoughts, just me, the beach, the water and the sky. The colorization of the water, the clouds and the sky seem to paint a happy glow, to bring to the forefront of the mind happy times while still reflecting on times of the past that were not so happy, a melding and blending of the two states of mind.
Great choice and god reasons too! I remember that evening well...It was red, sort of like Mars of something, not that I've been to Mars or anything. I like number seven too, no people and I like that it captures the texture of the sand in the foreground but a little further the sand looks like glass due to the water still running back off it. I prefer to see more clarity in the clouds but I think the interest comes from the contrast of the light in the water, the sunlight and shadow.
Thanks for playing along and letting me know your favourite and why.