I've only been using X10 for a year, so here is my all American rookie setup.
AHP with the plugins w/cm15
BVC
PC Companion
combo of pro rocker switches (dim/non dim)
X10 wireless cam
2 non x10 cams.
Ninja pan/tilt base
video sender
Stick a switches
palm remotes
eagle eye motion detectors
x10 outlet plugs
What I have setup and going is: I can monitor the front of the house/ front door. Video sender sends the multi cam view to my TV
in the living room, so I can see what is outside- or who is at the door. I've caught my kids in some funny play moments. I have a cam on the Ninja and have it watching the driveway and can sweep over to check the garage door. (this is used while away from home). I use a non x10 capture card for the cam to record and so I can monitor via my pda when not home (also can search recordings via the pda).
I have timers setup so the lights come on in the kids room, to help them wake up to get ready for school. Light will come on in my 6 year olds room, light comes on down stairs. His vision isn't very good, so this extra bit helps him get around when its dark in the morning.
I have a "night night" macro, when I hit the one button on the palm (or ask BVC), it sets off a timer to turn off the down stairs lights we use, then turns on the lights in the master bedroom.
I can use my pda to remote into my computer and use PC companion to turn on/off any of the lights. This is while away from home.
I use a motion detector in my little boys room so when he walks in during the dark hours the light comes on (although I did have to explain that the motion device wasn't a bomb planted in his room (he watches too much star wars).
I use a motion to detect if someone is coming up to the front door, to activate a light.
I gave the wife a stick a switch for her desk, have it set to control the kitchen and breakfast area lights, since the kids have a habit of leaving those lights on.
I have a stick a switch by my night stand, can turn on/off bathroom light, bedroom light or ceiling fan. Wife likes that part since she has a habit of running into things when its dark.
I have a wireless speaker system on my computer and have one speaker down stairs and one in master bedroom. I can either use remote or ask BVC to turn off appropriate speaker and activate the mic for that room. The speakers/mic's are on the x10 outlet plugs and an appliance module.
My setup is just the basic family guy stuff, who likes playing with gadgets and gizmo's. Nothing fancy. I know the others here have some awsome setups, but wanted to show what a regular guy can do and how it helps with the family.
Mike T