I would agree with Robert that you should contact a professional installer to go over what you want out of your home.  I found out the hard way that while I had anticipated some of the things I wanted to do with my whole house audio system, there were many other things I was unaware of such as intercom / security / automation which I could use some of the additional wires I ran through the house for.

Funny, I did wire my entire home with Cat 5 ethernet cable but I have found very little use for it. Everything seems to be heading towards wireless, and I have a good quality 802.11n router.

@Sam :
cat5 is almost a universal cable that is used for all sorts of control and automation applications.  Internet and networking can play a crucial role in video distribution as well.  Wireless is very prevalent for internet type applications, but fixed run cables currently offer superior bandwidth, and more reliable connections than wireless.

You may find a use for all of those cat 5 cables if you installed a multi room audio system, but you’d still have to run speaker wire anyway.

Alex:
I concur with Robert and Paul about consulting a Professional.  CEA’s TechHome® Division has a Referral Database that can be found at http://www.digitaltips.org.  By entering your zip code you can find qualified professionals that will assist in helping you determine the best system for your tastes and budget.

NuVo®‘s Essentia® six zone, six source multi-room systems may be a manufacturer to look at. Placing a rack under the stairs and combining the Essentia with a tuner and an inexpensive media center computer, you would have AM/FM radio, Sirius/XM radio (if you have a subscription), internet streaming and your CD collection available for any room or combination of rooms.  This system is Energy Star rated and provides Meta data at the keypads.  Russound, Sonance and the others mentioned in Robert’s response have similar systems. 
Again, a consultation with a professional can help determine which system or systems will meet your performance and budget criteria.

Another system to look at is CasaTunes.  They offer two solutions that will turn your PC into a music server they offer 5 sources of music to 6 rooms or 9 sources of music to 12-48 rooms.  The 6 room solution is great for the DIYer.

Thanks for all the advice lads, todate I still have’nt progessed on it as I just have’nt had the time, so hopefully in the next couple of weeks i will get the chance to do a bit more research!
Again thanks for the advice.

Alex

I agree with Wade. The nice thing about CasaTunes is that you really don’t need Keypads (although the CasaTunes keypads are nice). You can control it from any browser on any computer on the LAN, including the Safari browser on a Mac. CasaTunes just released its iPhone App giving you a nice remote control option on an iPhone or iPod touch, too. So, if all you have are speaker wires going to the area below the stairs CasaTunes makes a lot of sense.