After some thinking, a new Main Point Of Entry MPOE setup has been installed in the basement. The idea is to put Cat6 cabling into the entire house (actually, using the old phone-line conduits havong unshielded cheap cables), and the central hub of all the conduits was the basement.

The MPOE was chosen to be large enough to also host the first point of contact with the local Telco. In the current case ADSL, while end of the year fiber is planned. Note that moving the ADSL Modem into the basement and avoiding 10m of cheap quality telefone cable proved to be a blessing in terms of line quality. The ADSL modem average speed has raised from 12Mbps to 14.8Mbps, some peaks with 15.9Mbps have been measured.

So far a 16Port GB Switch handles the data-distribution to all rooms, while the ADSL modem provides internet access. As the Firewall, Server and NAS will move down into the basement, some extra space has been reserved for these in a nearby room.
A better view can be seen here