when it comes to buying the 'central' hardware to plug your Cat5 into, make sure that you get a 'Switch' rather than a hub. A good programmable switch can then be used to create different vlans (virtual local area networks) By doing this you can logically separate out all the traffic, i.e telephone, cctv, music, tv, games, etc...
I wouldn't bother with Cat 6 for the house, you can run speeds of gigabit easily over a good cat5 installation.
I would just use UTP cabling, rather than STP. Just make sure that you don't run the cat 5 cables in the same trunking as your power cables.
Any questions mate, just ask and I'll see if I can help