Do you have a satellite dish and LNB yet? Make sure to check out the FTA FAQ's to make sure you get the right kind of equipment needed to receive FTA channels.
Make sure the tuner card you get is compatible with your version of Windows 7 (32bit or 64bit). I am working on revamping my home theater PC to be something very similar to what you are talking about.
I currently use Window Media Center (MC) and also have launcher buttons within MC that launch Boxee and Hulu Desktop. Those are both used for internet TV. I have done some investigating and found some good sources for internet TV (Boxee pulls content from many of the sources in the toptenreviews):
Internet TV Sites Review 2011 - TopTenREVIEWS
Neuros.TV
My hopes are that I can use MC to handle my OTA and FTA tuners, and Boxee and/or Zinc and/or Hulu Desktop to handle internet TV content. I haven't tried Zinc yet, but I do know that Boxee will handle local media as well as internet TV, so I think that anything I record using MC, I can view using Boxee (in order to reduce the number of media centers being used by the user). Boxee's Netflix interface isn't as nice as Windows MC, but it is fairly new and I expect it to improve. Unfortunately, Hulu has blocked Boxee from pulling Hulu content onto your Boxee MC b/c they want you to use their Hulu MC (which only pulls content from one source - Hulu.com).
A 1.5 year old comparison of Zinc, Hulu, and Boxee:
Boxee vs. Zinc vs. Hulu
I would really like to see a program that adds all my channels (OTA, FTA, and internet TV) into one EPG, but I haven't been able to find such a comprehensive program.