How do I configure all Binaries to Publish to the File System in SDL Tridion 2011?

As far as I know, the less you specify, the less you filter. Have you tried omitting the itemExtension attribute altogether? I would expect this then to apply to any extension.

We use the following in our configuration and it picks up any new binary file types we add without require a change to the storage configuration:

<Item typeMapping="Binary" storageId="defaultStaticFile" cached="false"/>

You would just need to update to use your storage end point and desired cache setting:

<Item typeMapping="Binary" storageId="defaultFile" cached="true"/>

Just strip out the itemExtension node, and it will deploy all binaries to that storage id. The extensions are really only for exceptions.