Which Transmitter System

Hey guys,

a few weeks ago i decided to develop a home automation for the arduino platform.
I started a testing serie with the 433 Mhz frequency and a simple 433Mhz transmitter in combination with a ELRO socket.
The thing is, that i want to realize not only switching off and on power-sockets but even to control switches on a radio basis.

So what system would you prefer for that. I read about z-Wave, etc.
And how can i realize, that a switch sends his position via a radio signal?
I hope you can help me. The system should be as expandable as possible.

Kind regards
Max