For whatever reason…the GNOME people decided that menu / button icons were a usability problem. I feel the opposite way. I think the menu / button icons are absolutely a must have for usability. Icons make certain menu items stand out immediately. The interface tab has now disappeared from the Appearance app in GNOME which means you have to manually enable the options to display icons. This is easily done, just run gconf-editor in either the terminal or if you’re smart you have Gnome Do.
Once you’re there, navigate to Desktop -> Gnome -> Interface. Check off buttons_have_icons and menus_have_icons. These settings take effect as soon as you check off the options. Enjoy.