How we do it (Score 4, Informative)

Running in Conduit is nice...but very expensive. The stuff to use is around here referred to as Smurf Tubing due to its light blue color. I ran conduit all over the place but it is packed so tight that I will never get anything in without an amazing amount of work. In hindsight I would recommend running the tubing only to and from the attic and crawl spaces. This makes it relatively easy to make the long runs outside of conduit. One thing in favor of conduit is that in my house all of the walls (including interior) are insulated. Running cables through it without conduit is damn near impossible.

Run 6 RG-6 quad shield cables to where the satellite dish would.should go. Think about when you want the cables to come out of the house in order to avoid eaves, etc... HDTV over satellite I hear needs 4 cables alone and running these cables after the fact is horribly ugly.

In the house run Cat 5E for phone and data. In fact use RJ-45 female plugs for both phone and data. If you do things right in the wiring closet you can switch any jack from data to telephone (and vice-versa) without needing to punch stuff down. Running non-terminated fiber would be nice but when you need it 10 years from now who knows if the cable will be useful. I've seen houses wired with old Thick Ethernet ahead of time only to find out that its useless in a Cat 5 world.

Locate your wiring closet somewhere in the center of the house and on the second floor if you have one. Put your WAP here for ideal coverage. In your wiring closet plan for some ventilation in case you are planning on putting a house server in it. A cheap bathroom fan on a timer to such the hot air out into the attic is usually enough. Avoid carpet for wiring closet as well due to static electricity. Doing a build-your-own rack is not expensive and looks nice. Just buy the rack-rails and have the framer build your opening.

If you are going high-speed via DSL have the folks wire in the DSL filter in the home run. This keeps you from putting additional DSL filters on the line which can hurt performance. Leviton makes one for about $20.

Wireless is great and should be considered during construction but it won't ever replace a physical line. Think about telephones. The cheapest hard-wired phone sounds better and clearer than the most expensive cordless phone.

And finally, try and leave it to the pro's...at least the running of the cables. What you can and cannot drill is not obvious and the builder is likely going to jack the price a bit if you want to get in there and do it yourself. Cable jockies can run it faster and cheaper than you ever could and they pay much less for cables, jacks, and tools than we do. $3,000 to $4,000 built into the price of the home gives you a stunning amount of jacks and capabilities.