I would be interested in knowing how you set up the Server so that your outside internet connections "see" your web page, but are isolated from your internal network attached to your router/cable modem where your Server and HDD drives are.
I'm only exposing port 80 (http). That's a basic 'check the box' field. My Mini Server will be hosted at a colocation facility, but if you had a home cable modem and router, you would only allow port 80 and send it to the Mac Mini's IP address.
This is all do-able with a traditional Mac Mini, and MAMP or MAMP Pro.