If you are burying cables in the wall you may as well spend the extra and go for Cat. 6a UTP as it's spec'd to carry 10 Gbit Ethernet. Watch out for the minimum bend radius though its often around 30 mm with Cat 6a (4x cable's outer diameter).

More and more stuff can be carried down UTP like video (HDMI over Ethernet) and USB devices, it is also ideal for hooking up phones around the place too. You can never have too much UTP in your walls when considering possible future requirements IMO.

Oh and don't forget to run some up to your roof area to give you the option of participating in your local wireless mesh project!