Sydni, I really like the one with the open books, because if you look at it, it is perhaps one of the most dynamic and interesting. Lots of diagonal lines, and some alternating colors - yellow, red, green.
The one think I dislike about it is that the light source is so bright, and it is high contrast. I'd love to see that image only with a softer light source -- something more romantic or inviting --and not so harsh.
I think this photo concept is the best yet, to be honest, outside of a person making eye contact with the viewer. My vote is to find an image like this but only with softer lighting.