In terms of general Home Automation, oh yea I'm all over it already; I use my N800 to control lights, MythTV box/music, alarm (intrusion) system, phone system, etc. I even have it at the point that when I pull up the driveway the AP in my Jeep associates with my house and sends some signals causing the outside lights to turn on/etc.

It's not that difficult to do these things, especially with great linux-based devices like N8x0, embedded routers/small devices, etc. You just need to have some coding understandings and be willing to spend money. For example, I use Insteon light switches, which are absolutely awesome in terms of what you can do/how they look/etc, but they cost like $50-60 CDN each (some of the other techs like Z-Wave etc are twice that price), so you have to be prepared to spend some money. The easiest road for a straight up solution from my understanding is something like Linux Media Center, which offers things like orbiters for N8x0, etc... I just like to roll my own stuff so I have more control over how it works and the cool things I can make it do ;o)
(It's all about the little things too... my girlfriend is still amazed every time we sit down to watch a movie and the lights automatically dim as the movie starts!)