Hmmm...Is the television in that cubby area below the mantle?

I wonder if it might work to hang the television centered over the fireplace, then put any components in that cubby instead. You may even be able to put doors on it to tuck them away.

If you don't mind leaning a little more modern, a darker wall finish to tie it all together might help:
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Or, you can ditch the slab mantel shelf and change the orientation of the fireplace, making the most of the height in the room, which appears to be two stories tall:
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You can store many parts in another room or closet with an infrared remote unit http://www.smarthome.com/770204IR/Channel-Vision-E4200IR-Micro-Modulator-4-Channel-w-IR-Repeater/p.aspx