N/e one using 7 for home automation?

Like lighting control, turning the sprinklers on and off, etc...?
I'm thinking of putting the HTPC to use by hooking it up to the lights via a motion sensor so that when I get home and open the door, the sensor will wake the PC up, the PC will then turn on the lights in the house and play some music, turn the TV on, etc...

N/e one with this type of experience? I'm thinking a few motion sensors, some relays, and RS232 ports ?

i use the software from Home Automation Systems - HomeSeer i'm running it on xp and it works great but the websites says it supports 7 as well, however the requirements are very low and it's a great way to use an old machine you would otherwise junk or allow to collect dust.

and trust me you want this stuff. i don't know how i ever got by w/o it.

Yall mind elaborating on what you do and how it is done? Do you recommend certain systems over others?

I am interested the recommendations, also.