Mack...All good suggestions.
CG and Porphyre.....Straighten the TV up a little
MACK........Along with what THDEWEY stated, you may want to rethink a television up that high unless you can sit quite a ways away from it. I mounted a 52" on my wall to where the top of the TV was 1' down from the ceiling. I have 8' ceilings. It was great standing up and it was at the height that if I had a fireplace it would have to have been mounted that high. I had it up for about a month and down it came. The only way that you could watch it was from a recliner. Sitting in a regular chair you were constantly looking up. So either you had a headache from your eyes looking constantly looking up, or your neck started to get sore from looking up.
So before you go to the expense of buying your mount to hang it, and the labor of mounting the mount, take a little time and arrange your furniture to where it will be when you watch TV. Then sit in the furniture and look at your cardboard TV for an hour or so and see how comfortable it is. If you are going to get eye strain or neck strain you will feel it within an hour. With a TV that size you don't want to make a mistake. Myself, I was able to patch the drywall. Also when you are in a sitting position, look around the room a time or two and then notice what is a "natural" eye level. And not knowing anyones medical issues, but anyone with neck problems or even if you have a mother that frequently visits and has osteoporisis looking up is not a good thing.
Other than that, go for it. I also like the column idea to center everything up. I would not have thought of that one.