Non-working Fireplace inspiration

My sister recently moved into a new flat in London and has 2 non-working fireplaces. Here's a photo of the fireplace in her living room. Ignore the wires, she's still unpacking!

I really wish our house had a fireplace and have pondered creating a faux version, so I can't stop thinking about my sister's place. I found these photos on the interwebs for inspiration.

She could paint the inside a dark color and fill it with pillar candles. She has a cat though, so this could be a major fire hazard.

I love this visual of the books in the fireplace, although really, this will look messy in everyday life.

She can put a pretty decorative screen in front of it and use the inside for storage of video games/dvds, shoes, etc.

I like this idea of putting the TV inside the fireplace.

I actually suggested something similar to this originally, put some plants/art inside it.

I like this solution, she could pile a few real logs, drape it with white Christmas lights, and voila! instant "Fire"!

I also found a blog specializing in fireplace decorating.

Regardless of what she decides to do, I think she should paint it a charcoal gray or black to make it pop from the white walls.