"The Attic is usually very warm, even hot. You will want at some point to add hardware such as Ethernet switch, a sever, and so on. I would pick a central location like a closet.
Also I woudl recommend running your cables through conduit. It makes it much easier if you have to pull more cable latter.
Also don't forget to put in extra power outlets.
Last, run twice the cable you think you will need."
"When I bought my house, I was the first (and apparently only, as the builder has since gone out of business) to request the pre-wire option.
No one (on their end) really knew what they were doing; I didn't get all of the cables I specified, didn't get the condiut I specified, they didn't bring them out of the walls where I wanted, and even though I have a coax and two cat 6 cables coming out in each room, and a grand total of ~20 UTP and coax coming out in the ""server closet"" area, they were all brought out of their various walls through one box each.
Short version, whatever electrical contractor actually did the work didn't grok low-voltage, so, I'd strongly recommend that you make sure you get the opportunity to approve the rough work before the drywall contractor does their thing; it's much simpler to correct mistakes at that point.
Beyond that, +1 to Jim C and Kevin L; run more than you need, and since you're going to the effort, plan for speaker cables too."
