Yesterday I installed the new WP 3.7 at A Traveler's Library and it screws up the visual editor on my site. (Fortunately my problems are not as serious as other people seem to be having). The public view of the site looks fine.
On my theme, Blue Grace, there is a gray box that stretches way beyond the borders of my editing box, and does not show the picture that I have entered. In the text version everything appears correct.
I tried disabling all my plugins and that did not solve the problem.
I switched to various themes, and the visual editor worked correctly only on Twenty ten, twenty twelve and twenty thirteen of the ones I tried. Some themes showed the gray box, with the picture somewhere within it, some just the gray box.
I am now reverting to my backup before installing 3.7, but am hoping that I'll be able to go back to 3.7 at some point.