My Vista IIS 7 box recently stopped listening on the localhost ip addresses for no apparent reason.  I don’t know how this happened but I eventually found the solution.

I ran across the following command line that lists all the ip addresses that IIS is listening on (but I'm not sure how this differs from the IIS web site bindings):

netsh http show iplisten

This showed one ip address, which was my machine's ip address.

I ran this command on another vista pc that was working and it returned an empty list.

I then ran the following command line to remove the rouge ip address from the list:

netsh http delete iplisten ipaddress=192.1.1.123

Once I removed the ip address so the list was empty (which is what I have on another vista machine for comparison), localhost started working again.

FYI: This also applied to .NET WCF endpoints.

I believe the httpcfg command can do the same in older Windows OS versions.