Cat6 all round to connect all the "end-devices"
You might want to consider using fiber for all "rackmount-devices"
You'll need a 16 port 10/100/1000 switch, with fiber uplinks - i think 16 ports will be enough to cover each room, incl. the toilet?
Your living room will probably have 4-6 wallboxes, to support your xbox360, dstv hd pvr decoder, bluray player, etc...
You do get HDMI to LAN converters, so you could in theory stream your DSTV HD PVR decoder's signal via the LAN to your streaming server, to the rest of the house.
For laptops, you would want ideally one or two Wireless Access Points, i.e. living room and bedroom, and maybe the toilet. (I use my iPhone wireless all over my house, which is connected to ADSL router)
In the end, it matters about the physical connection a device has. i.e. your laptop does NOT have a fibre connection where you can just plug the fibre in, its still based on RJ45 connector. Same with bluray player, PC, or any media player with network capabilites... its NOT going to have a fibre connector at the back (and NO, you cannot plug a fibre network into the optical out[sound] ... lol)
You could buy a rackmount server with RAID-HDD config, and a fibre NIC, which will stream all the video to all your devices
Ja, a network diagram is where you'll want to start (use MS Visio)
If the project is big, give it to professionals to do
Enjoy and good luck