In Leopard, you get a lot more control over the layout of your desktop. You can control the icon size, spacing and arrangement; the text size and location; and also if the icons are previews of the file or not. To get to this customization screen, click on your Desktop. From the menu bar, select View and then Show View Options. Once you do this, you'll get the following panel:

Desktop Customization Panel

You can change the various entries in here to give you a nice customized desktop in Leopard.