Things I learned wiring our house two years ago:
1. Always put in two more wires than you need. Wire is cheap, retro wiring is not. I would have had to add wires for Sirius radio tuners, whole house modulator feedback and two extra antenna wires for my new TiVo boxes.
2, Add much more Cat 5e or Cat 6 than you think you need. In just two years, I've networked two DVRs, a Roku, a Slingbox, a TV and a Blu-ray at one location in the family room. Eventually, network switches hung all over the place does not get it. Evryting is networked, or will be. Cat 5e or Cat 6 is really cheap, but not if you don't have it. Don't forget the possibility of HD over Cat 5e.
3. Wire for fiber optics, even if FIOS has not made it to your neighborhood yet. Run the Cat 5e or Cat 6 to the corner of the house in the the garage, and have a power outlet there. You may want it later.
4. Wire for an antenna, in the attic if it will work there-we put ours just below the edges of reflective attic roof coating, inside. Works great.
5. Obviously, don't forget lots of electrical outlets. All three of my home theater full setups have two seperate, 20 amp dedicated lines on opposite rails in addition to regular plugs. Glad we did that. You will always want more plugs.
6. If you want to put your stuff in a remote closet or cabinet, make sure plugs are there, that HDMI, subwoofer and speaker wires go exactly where you want them. Provide for A/C or ventilation-a bigger rig generates a lot of heat.
Maybe you should just take everything you think you need and double it. Wish I'd done that, but I did not allow for satellite radio, extra antenna lines, modulator feedback lines, networked Rokus, Blu-rays, TVs and receivers, etc. Fo sure, you will need ,more lines than you thought sometime later-just have them there-we have nine RG-6 cables running to the family room and use them all.
Get someone who knows what they are doing and wire for the future, and maybe not just DirecTV secific. We had D* for fourteen years and just switched to FIOs....
Happy building!
P.S. you could even future wire for active speakers. Two friends of mine have switched to Martin Logans or Maggies in the last year-both wished they'd put plugs about where you'd put the speakers. Big Def Techs? More plugs!