I don't bother shooting open water landscapes with a cloudless sky, it simply leaves too much of the image bare. Nearly the top half of an image being a zero sky combined with a fair whack of the bottom half being a reflectionless water, it doesn't leave much going on. Not that it's awful at all but it's just not winning any awards, that's all.
I like number five the most but I think they're all pleasant. Considering my first paragraph, in these circumstances if you really want it to work, getting down low on a tripod with something in the immediate foreground taking the main interest of the shot, eg weeds, a tree stump, a tree etc is always valuable and makes up a bit of ground on an evil sky. That's why I always have a tripod in my ute, just in case.