Which RPG has the most jaw-dropping layout?
I'm going to go with the 5E Monster Manual. There are so many to choose from that I have to go with one of the ones I have seen most recently. I actually like the way they integrate the monster pictures with the layout where they are not always in neat little boxes and instead overflow into other boxes/areas of the page without being obtrusive. They also did a nice job adding sub-boxes of interesting tidbit information on the monsters for some of them that enhance the monster description while making the point unique. You can also tell they purposefully tried to keep descriptions and stats on one page per monster, thus making it easier to read and follow. They did an excellent job. Would I call it jaw-dropping? No, but their attention to detail is excellent with this product and one of the best.