In the vCenter Client, since vSphere 4, you can find a Storage Views tab on several of the VI containers. The data in these Storage Views is collected and provided by the vCenter Storage Monitoring plug-in.
Have a look at David Davis‘s post, called Using VMware vSphere Storage Views, for more information on what you can do with the Storage Views.
Some time ago I got a question from Andrew how the Multipathing Status presented in the Storage Views could be detected and reported upon by a PowerCLI script. What looked rather simple at first, turned out to be a bit more difficult than I anticipated.