As Constantin suggested, here is a list of services, which my home server should provide:
The server will continue to run Mac OS X and OpenSolaris, as the first goal on the above list requires Mac OS X and I haven't found an acceptable PVR solution for OpenSolaris yet. This is currently done using an Mac mini with Mac OS X and running an virtualized OpenSolaris on top of it. In the future, there may be two distinct servers due to some limitations of this constellation (e.g. having to stop the OpenSolaris server to install Mac OS X patches).