What you are asking is certainly doable but there are a number of different ways of going about it depending on what you are looking to do. I'll give a few examples, then you can post back if any of them seem like they may work for you. In any case, to distribute content through the home, Cat5e or Cat6 wiring is highly recommended. This will give you the most flexibility in terms of hardware.
1. HTPC + WMC extenders.
In this case, you would have a single computer acting as a hub to store and distribute content. Extenders are either Xbox 360 or Ceton Echo which connect to the HTPC over ethernet. The HTPC would run Windows Media Center and would be able to store a media library of DVD/BR rips, as well as play and record Live TV. Live TV could be either subscription content via CableCARD or OTA/ClearQAM.
2. HTPC + other streamers / smart TVs (this is what I do)
Here you could have the same setup as above, but instead of the WMC extenders, use a combination of smart TVs and streaming devices like the WD Live. The media library on the HTPC can be shared (windows folder sharing) so the streamers can see it and the Smart TVs can access Netflix, Hulu etc on their own. To share the HTPC DVR functions, you could use something like MCE Buddy to convert the recorded programs to mkv / avi so the streamers could play them.
3. HTPC + other sources with HDMI over Cat5e matrix
This would be a bit different in that all the sources (HTPC, BluRay etc) would be in a central location with an HDMI matrix distributing the content to several TVs. The downside here is twofold: first, each source can only be duplicated, not played independently so if the HTPC was playing Live TV, everything tuned to the HTPC on the matrix would be playing the same channel (however, a true matrix can have each TV playing a different source). Second, you would need to figure out a control mechanism such as sending IR signals back to the media closet.
In the first 2 methods, the main viewing TV is connected to the HTPC directly (or through an AVR). Each method has different advantages and disadvantages. I do the second method as it was the cheapest for me to set up and works very well for my needs.