My Denon AVR-487 receiver has 2 optical inputs. I'm going to connect my DVD player to one. Now for the second input should I connect my Dish Network 942 HD DVR or my Samsung LNS4695D LCD 1080P TV?

I will be connecting both my DVD player and Dish Network DVR to the Samsung via HDMI

Thanks

Then you don't need to connect the DVR to the AVR via optical. The DVD also plays CDs, so it might make sense for that (or it might use HDMI for CDs). No reason to connect the TV audio (in or out) to the AVR. Don't use the TV speakers at all. Turn them off.