I've followed the steps as per this guide and unfortunately still cannot get the subnavigation to work? http://www.heathersolomon.com/blog/archive/2007/05/15/SharePoint-Tip--How-to-Activate-the-Drop-Down-Menu.aspx
The settings under 'Navigation' are just fine, and in Sharepoint Designer I changed 'MaximumDynamicDisplayLevels' under the 'TopNavigationMenu' but still no joy, it won't show any sub navigation.
Thanks