The default place is under "preferences - customize look and feel " you can install icon themes here, change looks, etc. The wallpaper you can use whatever you like for an image. Just right click on the desktop and choose "desktop preferences". using themes, icons, and wallpaper from gnome-look, or any of the "look" sites is fine. They all mostly work. You could get some mixed results, but thats part of the fun of playing with them right? ;) biff
PS...the menu icon in the lower left hand corner can be change by right clicking on it and going to "menu settings" and choose whatever image suits you as well :). enjoy