Our old house in Reno, NV had a horridly ugly fireplace made out of cemented faux 70's rock. It's hard to believe that at one time it was considered attractive but apparently it was since I've seen the same fireplace in many homes when I watch renovation shows on HGTV.
There's just nothing you can do to make it look better. Even the good old DIY'er trick of painting it white wouldn't do it. It'd probably just make it stand out even more, making it painfully obvious that you tried to cover up the fugliness of it.
One day at the beginning of our renovation process (read about that here in this post!) Dave got a sledge hammer and just started swinging away. Yep, that's generally how we did things. No real planning or anything smart like that. We'd go from sitting on the couch to literally swinging the sledge hammer and taking down whatever ugly thing was offending us.
So Dave swung away and then eventually switched to a crowbar, leaving a giant pile of debris to the left of the fireplace. (We were planning a trip to the dump that weekend so we just piled it up until then. We also planned on laying wood floors later so we weren't worried about the carpet.) Even with the debris everywhere and no drywall it looked so much better!
After drywalling the fireplace we choose grey/tan slate facing panels for the front with matching hearth stone tiles. The panels are pretty easy to cut to length and mount with mortar to the wall.
We attempted to do the mantel ourselves by purchasing mantel pieces from Home Depot but quickly realized that cutting the pieces to fit and mounting them was a little tougher than we thought so we had the guy who was working on our kitchen do the dirty work for us.
Please ignore the line up of ugly tchotchke items on the mantel. All of that was just laying around on the ground so we plopped it up on the mantel to get it out of the way. All except the lovely golf trophy which Dave thought deserved a special spot on the mantel. It became a game with us. I would sneak in, take it down and hide it and then somehow it would eventually re-appear in the same spot.
Finished! Complete with wood floors... even the golf trophy managed to sneak its way into the photo.