if you have everything hooked hdmi run all that to the tv, then run an optical cable from cable box to the tv. It all depends on what sound you want coming out of the receiver. Remember this easy point. if you want start with the cable out of the box put that hdmi to the tv, run an optical cable from the optical out on the box to the optical in on the receiver. you didnt mention and dvd player. the box depending on it you want that sound to come out of the receiver would also need to be hooked up to it, mine there again is optical and then I go hdmi to the tv.
For me it came down to the number of HDMI inputs in the TV versus the number of HDMI outputs in the receiver and which device I wanted to control the various inputs.
I used HDMI connections from my DVR, Blu-ray player and streaming video player to the TV and the audio out from the TV to the receiver. That way I only used one input on the receiver and used my Comcast remote to change the inputs on the TV.
Worked like a charm.
I could have connected all devices to the receiver with HDMI and then used another HDMI cable to the TV and then controlled the various inputs through the receiver. However, that was less efficient for me because it would have required one more HDMI cable and the Comcast remote wouldn't change the inputs on the receiver.