I'm also a Satisfied X10 User, and have been one since the middle 1980's. I got a CP290 interface and DOS software at a now vanished Heath store on Joppa Road near Loch Raven Boulevard in Baynesville, a suburb of Baltimore. A good friend of mine introduced me to the world of X10 and also sent me to Radio Shack to get my first lamp modules. I started small, with 3 modules in the Living Room and one in the bedroom. As the years passed, more light and appliance modules added and I discovered a local X10 dealer in Upper Carney, and a built-in module to control my kitchen's fluorescent light and modules to control my lamppost and porch light. I now have SS13 "Socket Rocket"s controlling both lights in my attic and basement, plus wall switches both lamp and 3 way wall switches in the bedroom, kitchen and laundry room.
My X10 controllers have been a CP290, a serial interface and assorted DOS and Windows software, that was replaced by Active Home and the CM11A serial interface and now Active Home Pro and the CM15A USB interface.
My wife loves X10, we never come home to a dark house, lights come on at 6:15AM on weekdays for my wife (she's a teacher), and go off between 7:20 AM and 7:45AM when I leave. Timers turn on inside and outside lights as dusk starts, they stay on until 1:00 AM. A key press macro (A5 OFF) triggered by a keypress on a MC 460 Desktop controller that turns of lights on 3 different housecodes.
BTW, I don't have any of the plug-ins for AHP, don't need any of them.