I will answer your cabling question from experience with finishing my basement as a theater room four years ago.
I new I was going to get HD, and have an off air antennae, but did not know I was going to have a HDDVR in the future. I also had an XBOX at the time that was connected to my home network, so I knew I was going to run a Cat5 line.
I did all the cabling myself. I used to be an electrician, so it was no big deal for me. In my situation, I had the Cat5 line, two RG6 lines (one for the antennae, and one for the Directv). And I also had speaker lines for my surround speakers.
My mistake was I did not run an extra RG6 line. So the other day when I had my HR20 (HDDVR) installed, I had to run another line, and now that it is all finished it is harder to run. I also ran another Cat5 line, since the HR20 is going to be networked in the near future. I do not have the XBOX anymore, so I had an available Cat5 for the HR20, but with home media becoming more and more dependent on the internet, I ran another one anyway.
So my advice is this. Hire a contractor to run the lines for you. You will probably pay $300-$400 for the labor plus the cost of parts, but it will look nice, and he can pull Cat5 and speaker lines if you want, whereas Directv will only pull the RG6 lines for their satellite. Plus as mentioned before, the independant contractor will do a nicer job.
Also, pull four RG6 Lines, and at least two Cat5 lines. As I have experienced, just two RG6 lines, and one Cat5 line is not enough. Always pull one more than you think you will need!