On #1, I agree with you. The color is needed.

On #2 & #3, though, I like the monochrome, because I love the way the sky looks in them. Plus, the colors are typical of what you would see.

On #4, I prefer the color version, because it is different than the typical you would see.

On #5, I'm torn, but mainly because sepia isn't something I like as much. I could go either way.

#6 could go either way, too. I like the color, but for some reason that monochrome makes it look so different and that flower stands out better.

#7, I like the monochrome, because it makes it look so much different than the original. I'm not a beer drinker, so maybe my vote doesn't count on this one.