By "lock in" the HDMI audio, I wasn't sure if plugging an HDMI cable into the outputs would disable the other audio outs. Trying it seems to indicate that it doesn't, as you said. Although for some reason, the center channel from any source that has discrete channels is either non-existent or the dialog sounds like it's underwater. Wonder if I somehow managed to reverse the polarity on one end of the speaker wire?
I am running the HDMI straight into the TV, and the digital audio from the Blu-Ray and Directv straight to the receiver. I believe that's what you suggested above, sorry if I didn't clarify that in the OP. I wasn't aware that the optical audio didn't carry the same multi-channel fidelity as the HDMI, looks like it's time to start researching an AVR upgrade. I love my Denon 3805, it's a beast. I have to decide if the improved audio is worth swapping it for a newer model.