You can try hiding the fonts you don't use instead. This way, they don't show in the list but will still be available to system apps. http://lifehacker.com/5516306/how-to-hide-fonts-in-windows-7-that-you-dont-use

If you want to go back to a "out of box state" the following link lists all fonts supplied by Windows. Some fonts may not be present in your current localization.

http://www.microsoft.com/typography/fonts/product.aspx?PID=161

The following link (about.com) has a list of fonts which are said to be required. However, I would not fully trust it as for examplle the Segeu UI family is not listed while widely used by Microsoft applications.

http://graphicssoft.about.com/od/aboutgraphics/a/fontoverload_3.htm

On top of that the following link says not to delete any font with a ".fon" extension.

http://graphicssoft.about.com/od/aboutgraphics/a/fontoverload_3.htm

While I don't see the need to remove fonts (unless you installed like 1000 of them) my suggest to just do it carefully, backup, remove one-by-one approach, and regularly restart Windows to see if certain UI objects were changed to the point you can't use them.

Best practice in manual font management does not start with removing unnecessary ones but by only installing those necessary. At best use a font management tool which simply allows you to "activate" and "deactivate" third-party fonts on demand.

http://www.xiles.net/nexusfont/#features (random example)

Fonts supplied with* Windows 7

http://www.microsoft.com/typography/fonts/product.aspx?PID=161

Windows Fonts That Should Not Be Deleted

http://graphicssoft.about.com/od/aboutgraphics/a/fontoverload_3.htm

http://www.instantfundas.com/2007/10/windows-fonts-that-shouldnt-be-deleted.html

How to remove Windows 7 non-latin fonts

http://www.support-ing.net/how-to-remove-windows-7-non-latin-fonts/