Because the geography related infobox templates are "owned" by a variety of Wikiprojects their look and feel varies considerably. For example, Template:Infobox City, Template:Infobox U.S. state, and Template:Infobox Country currently have three distinctly different appearances, and a user traversing from Boston, Massachusetts to Massachusetts to United States sees each of these. Style differences between these templates include:
I propose we adopt guidelines roughly like the following:
1) These guidelines shall apply to Template:Infobox Country, all similar country-specific infoboxes, and all city and national subdivision infobox templates, collectively called geographical place infoboxes.
2) All geographical place infoboxes shall use CSS class infobox geography, as defined in common.css with no style overrides.
3) No geographical place infobox shall use embedded <br> in corresponding label and value cells to define subrows. This technique makes the content difficult to understand if using a non-visual browser (such as a screen reader).
4) Row labels shall use the HTML TH tag (or wikitable equivalent, i.e. !).
4) Collections of related rows shall use no CSS styles to create or inhibit borders other than the mergedtoprow, mergedrow, and mergedbottomrow styles definied in common.css.
Note that the styles that are referred to are not (all) defined yet. As a starting point for discussion, I suggest we first agree on the general principles (as above) and then work out what the styles should be.