If you want to control your lights and fans and what not, got to lutron and get their Radio Ra Line of switches and controlers, It's all wireless.
www.lutron.com/radiora/
If you have a large home a X10 system can become unreliable ( I'm speaking from experiance here). Any home larger than 2000 square feet should not use X10. I would get something a little better.
OR if your REALLY serious about Home Automation and are willing to spend money on a custom designed system goto
http://www.amx.com/solutions-commercial.asp