If the HT receiver doesn't decode Blu-ray sound formats (Dolby TrueHD or DTS-HD Master Audio) or you're not using a Blu-ray player, then an HDMI connection to the receiver for sound is not necessarily required and the HT receiver could be connected via an optical or coaxial digital audio cable.
Most HD TVs have multiple HDMI inputs and either an optical or coaxial digital output. You can connect the cable box, DVD player and any other HDMI source to the TV, and then the TV would be used to switch inputs. The digital audio output of the TV would connect to the HT receivers digital audio input, which most should have.
Steve