Understandable. It does increase everything (I actually used that to make the other parts of the UI easier to select from a distance).
I can't seem to find a very detailed list of each element. But you can work in reverse. Pretty much every element in the list box correlates to an item in the preview window at the top. You can actually click any part of the preview and it automatically selects the item in the box. If you know you only want the font in text boxes to be larger, click the example boxes' text and then change the font size.
If you use Aero, some elements get skinned by the theme engine, so selections made here won't take effect (mostly colors though, font sizes will change).