Home automation (the term) has changed over the years (at least for me). In the late 1970's while still in school I rented a 4 bedroom home. Around that time I decided to "automate" the light switches in the home. It was a simple set up with an X-10 timer.
Did a quick home automation wiki search....interesting new name they give home automation - domotics
Wiki
In the early 1980's continued to utilize X-10 in the first home I purchased. Still very simple just controlling exterior/interior lighting. Sometime in the 1980's purchased an "alarm" panel which had built in speech processing for its multiple zones (think it was something like 32 or 48 zones). I liked the concept and started to put speakers in different rooms in the home attached to the panel. The developer of the alarm panel and I spoke in the early 1990's about its integration with X-10. The owner/developer showed me documentation relating to a prototype he was building. I don't know if it was ever sold.
While moving into the late 1980's I played with a Commodore Amiga computer and some early X10 and TTS applications. TTS was very primitive and machine sounding like.
Sometime in the 1990's migrated the X10 control from a timer to a MS Windows 3.1 application installing it on a very small footprint PC (concurrently played with CRT touchscreens and "light pens"). I still have the PC today. It as a point of sale machine with the footprint a bit bigger than a slip printer. It had a built in NIC (one of the first of its kind) and multiple serial DB9 connections. I think it was an Epson or Seiko device. The box was my first "automation" computer as it was only set up to manage my X10 switches via a Windows 3.1 program. Attached are some pictures.
The first HS server that I used for over a year was a legacy free PC called Easy Now (Sunflower). Purchased it for about $70 barebones. It ran fine for about 2 years (around 2001-2003). Here's a picture of it.
Sometime in the early 2000's (late 1990's) started to play with Homeseer. It provided some interesting features - X10 control and TTS; some flexibility with scheduling and some very custom "home automation" type plugins. Today I continue to utilize Homeseer and its evolved some with the term Home Automation. Concurrently about 7 years ago purchased a new alarm panel (HAI OPII) with some "built-in" home automation features; lighting, HVAC, sound, etc. I utilize both today for my home automation. My Homeseer server talks to my HAI OPII. I prefer to keep most of the lighting/HVAC events on the HAI OPII (primarily a security panel)
I continue to utilize X-10 today. Years ago migrated all my X-10 switches to Insteon and utilized both of the powerline protocals. Today I have X10, UPB and Z-Wave connected to my HAI Panel and X10, UPB and Insteon connected to my Homeseer server. My HA server today has over 18 direct serial connections utilized for various gadgets I keep playing with. I don't use the server as a primary lighting controller, nor HVAC but rather do things like manage my water sprinkler system, weather station, news sites screen scrapes, etc. I am waiting for the light switch that actually reports power usage. Here's an attached drawing of the serial connections to my Homeseer server (plus other stuff).
I like weather so I upload my weather stats to WeatherUnderground utilizing my HS server and automated my sprinkler system (using a touch screen).
Personally my take is that the best intro into Home Automation for a newbee is lighting control. How you do it and what you utilize is up to you. Its simple and has evolved much since the 1970's.