Advice needed for Halloween project

I am a noob when it comes to using the Arduino but I do have a good electronics and computer background. I am planning on building a project for a Halloween display at our house this year and need some advice on what parts would be best to get.

The plan is to build a laser tripwire that when triggered would send a signal to a control unit that would trigger lights, fog machine, sound effects, etc. I have found instructions for building the laser tripwire but I am not sure what type of wireless transceiver to use to get the command to start the display to the control unit. Xbee was my first choice but I also don't want to spend hundreds of dollars if there is a cheaper alternative. The distance involved is less than 10m so is something like the On Shine 433MHz transmitter/receiver suitable? Ideally, I would like the laser trip wire to be direction sensitive so the display only starts when someone comes to the door not when they are leaving. I think this is just a matter of using two laser pointers and two photoresistors and only transmitting the start signal if beam one (the one closest to the road) is broken.

The control unit I am less sure about what is needed. I am not sure what would be needed to interface the Arduino to allow it to switch on and off the lights, fog machine, etc all of which will be running at 120V.

Thanks in advance for any suggestions!

Why a laser tripwire ? , wouldn't you be better using a Ultrasonic Range Finder like:-

http://robosavvy.com/store/product_info.php/cPath/27/products_id/214

That way you should be able to tell if the target is getting closer or moving away ?

a xbee will work o.k for 10m , but you are right not the cheapish way to transmit data.

Well, I thought I would use the laser trip wire because I had already found some guidance on building one on another site but more than that it seem like a cool project! ;D

I've decided to spend the extra money get the Xbee's. I figured it would be better to get something that I would be able to find lots of examples and help with and that I could reuse for other projects.

After some more research, I think the simplest way I can find of controller the lights, fog machine, etc is to use X10 equipment connected to the control Arduino.

Should be fun!