One of the most annoying things I find using SiteCM is that when you add a border to a table it is ugly. It's that grey beveled thing reminiscent of Netscape which makes me cringe a little. Solution style the border in my css so in the event that the client adds a border to their table it will, by default, write out a nice smooth single pixel border.
border-width: 0 0 1px 1px;
border-width: 1px 1px 0 0;
See how easy that was? And the result is that the page went from writing out this:
Ah....much much nicer.