Just a couple of Idea's, depoending on how far you want to go into the automation thing, but as you are talking about DIY, there are a couple of options you could look at:-
1) Multiroom audio. There are a lot of multiroom audio systems about now, but you would be looking to spend a couple of grand for these. You should perhaps look at an expandable type of set up where you can start small and build it up as finance allows. I have had two multiroom systems in my house (one wnet bag with a lighning strike). The first was a wired system, with all mounted kepyads, and speakers in the ceiling. everything was wired back to a central room (a cupboard in the utility room), where all my audio equipment was, inlcuding cd jukebox, radio, video , dvd player and sky box. It allowed me have indepentned control of any of these devices in 6 rooms (audio only). Got it four years ago, was great then but these types of systems are becomming out of date. I replaced my system recently with a new system called SONOS (
www.sonos.com). Have a look, I would highly recommend it if you are looking seriously at multirrom audio. It is the bees knees, its scaleable, (start small and add rooms as you want), it is wireless, which means no limitations if you want to change thiss about, it takes about 1 hr to install. Each zone actually also gives you a 4 port ethernet hub for you to connect any other ethernet device onto your network also. Cant go into all the detail in this post, but ahve alook at the web site, and you will get more info. It is also the cheapest way you will do this, and you will not regret getting this systems
2) Video:- Just run loads of both coax and cat5 cable from every room you will be having video in, back to a central point. Look at what media centre is doing, I really think that is the way to go, for video, and its futureproof. Cat5 is always better than wireless, but you could do it wirelesly if you wanted, or a combination of both. The xbox post above loks very interesting, I must investigate it, but you could tie this into the SONOS box very nicely indeed.
3) Heating and lighting: DIY again, the best option to go for is X10. I have had it in for 5 years now and it works great. I have web,wap and remote phone control for all my lighting and heating. All my devices can be controled from any room in the house, via an infra red control and via a tv menu system. I can go to bed at night and with one press of a button on my bedside locker, trun off every device in the house, and activate the alarm system. This is all DIY stuff, all scaleable, and affordable. Very reliable also, has been around for years, just we europeans are abit tehnophobic. look at for info on this and multiroom stuff. X10 can easlily be installed in new or existing houses wihtout any additional wiring as it sends control messages over the existing mains wiring.
4) Security:- Again, DIY securirty systems, integrated into your automation system are availalbe, and very affordable. Wireless or wired, whcihever you want, but wired would be best. These devices can give you remote self monitoring (notify you of faults, power failure, breakins, phone messages etc), but also allow you to dial in and control your devices remotely. I have a "Comfort" alarm system, whicih I reckon is one of the best of these types. Its a bit more expensive that a normal alarm system, but worth it 10 times over.
All of this is scaleable, you can start small and build it up, wiht just a liitle bit of planning up front, and beleive me it is all DIY stuff.
Sorry, but I get over excited when I start talkin about this stuff!! There are lots of places you can buy all of this gear, in the UK and now in Ireland also. Take a look at
www.letsautomate.com for uk prices, which I think are better priced than ireland. I have ued these guys for all my x10 and security gear and they are faultless.
Wexfordman
Edit: Just looked at the Exstreamer post you had above. Sonos is far superior to this system, have a look at
www.sonos.com