You can get cheap USB stick type ATSC tuners and add them to your HTPC. Windows MEdia center can be told which channels to record from cablecard tuner, and which channels from the ATSC tuner.
We have a Ceton InfiniTV 4 and 4x Magica USB tuners, and dedicated the USB tuners to unecrypted channels (same as OTA, but fed through fios) and ceton is deicated to encrypted channels.
Media center extenders will let you view, live, pause, recorded, or set recording TV content, and all of you music, video, pictures, and movies on other TV with just a remote control. It is literally like having a DVR or HTPC at each of the TV' except that you can't really go online with those.
6 TV's in the house on FiOS and we only pay $4.99/month to connect them all!!! Power to the CableCard and WMC7!!!