You'd need to buy at least two dual tuner receivers, such as the 322, which I believe are around $150-$200 each. Then you'd need two DP34's (if you can run two cables to each tuner) which are about $30-$40 each, or a DPP44(if only one cable goes to each room) which costs about $200.
AND if you want more than 2 HD TV's you will need to spring for another HD DVR receiver ($$$) or dual HD receiver that will only operate 1 HD TV (TV1)...or a single HD receiver per "extra" HDTV
So your count of HD TV's that you want to watch high definition will dramatically change the $$$ needed to get your house going....
I recommend getting the DP 44 switch as it will cut down on the spaghetti of cables needed....1 cable per room instead of 2 cables going to each receiver...