Usually when I designing a web site I always show the full hierarchical structure when someone drilling it self down to a sub page, pretty much like the Windows Explorer tree navigation. Like this for example when a surfer visits the page "Subservice item 1":
1. Home2. Services 2.1 Service Item 1 2.2 Service Item 1 2.2.1 SubService Item 1 2.2.1 SubService Item 1 2.2.1 SubService Item 1 2.3 Service Item 1 2.4 Service Item 13. Products4. About us5. Contact
This approach unfourtnually generates a pretty big menu that is seldom suiteble for horisonatal navigation. How much do you expose of the menu structure? Often I see web sites that just shows the top level menu making it hard to show the surfer where they are in the structure.