Human Friendly URLs shouldn't have any Tab IDs in the URL. It should just reflect the hierarchy of tabs (i.e., http://www.engagesoftware.com/Blog.aspx for the Blog tab), and potentially other query string parameters (which you can't really get around).
The problem with something like www.google.com/images is that IIS won't forward that request to ASP.NET unless you (1) run every request through ASP.NET, which isn't recommended for performance reasons, or (2) physically create each of the folders that you want available, and then add a default document that IIS will forward to ASP.NET (usually Default.aspx). You'd also need to setup URL Rewriter rules for each of these URLs. This can be quite a bit of maintenance if you want to do this for your whole site.
I hope this helps,