I am just the man to talk about this. I have a very complex configuration where I have Windows Vista Media Center with the H20 connected to it and 3 Xbox 360's that get video from it. I also have 1 HR10-250 and 2 HR20's all of which are in the basement but feed 4 rooms in my house. Here are the different configurations I tried and currently use.
I love the Media Center as it is a nice menu and speed is great. It does OTA HD but is limited by HD capturing from Directv. It can only get video in via S-Video. Forget 2 Directv tuners too. So while it is a great DVR with tons of configuration options, its not a full HD multiroom DVR. So while I love its ease to setup a room with TV via a networked Xbox, it is HD limited.
So being an HD nut, I have it spread through my house via CAT5 wiring using balun converters, 2 HDMI feeds in the wall, and one component HD feed. I use matrix switchers that are next to the units to switch the video feed to the rooms. Its done via wireless remote extenders in each room.
See my list of stuff here.
http://www.satelliteguys.us/living-edge/101519-whats-your-setup.html#post957928
I recommend an all house serving configuration. You cant really get 2 receivers to talk to each other unless you go with the newer non-Directv Tivos. So you can setup a matrix configuration by having the units in one room but also feed the other room. Use either the CAT5 and component baluns or you can use CAT5 with even S-Video if going non-HD.
Just get a scenario where a matrix switcher or splitter to dole out the video to the 2 rooms. Then you can use a remote wireless extender.
Is this too confusing? I can stop and let you ask questions first.