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Digital Imaging by Tina - Interior Designer Depending on your style and color preference there are variety of ideas; but here are a few photos to help you decide on where to start...Houzz "Digtial Imaging by Tina"

Becca Stephens Add a low window seat with a cushion in the bay window. You have an awesome view so it would be a place to sit and look outside.
Fireplace, don't know where you live but check places that have old fireplace surrounds. Then add stone around fireplace then the surround stained or painted with the colors you like.
This is a blank canvas!! Good luck.

South East Installation Solutions, LLC you could install custom plantation shutters on the bay window, several companies offer a frame specially made for bay windows...

Digital Imaging by Tina - Interior Designer I'd place a flat screen t.v. above the fireplace; giving your surrounding wall some detail by placing stone work, in the backdrop, as shown in my image below...Houzz "Digital Imaging by Tina" www.brentsinteriorpainting.com

miskenack A nice mantel for the fireplace to have your tv to sit on would look nice.

cath99 Thanks for your comments

Backyard Biosphere I don't like the tv too high on the wall, what about next to the fireplace, you could do a modern built-in with door to close everything up for a sleek front when you are not watching tv.