Depends on the theme of your tank and if you plan to keep equipment in the stand...
1. If you're going for an SPS theme, try and make your tank as low as possible as your colors are richer when looking from top-down.
2. When I had my in wall, my tank started at 4ft. It was good and eye level, but the color richness was stronger from a 45 degree angle.
3. You can get away from 1 & 2 if you have angled lights. However you have your lights shining on the coral, is where the color will be the richest.
4. Rimless tank is also better lower as it you can see the beauty of it.
5. Are you keeping equipment under your stand? If you are, make sure you get size everything and make sure your stand is sufficient.
6. Do you have kids? If so, may want to go a bit higher. You dont want any accidents if they can touch it.
7. How tall are you? level your tank to how you would like to see it. You may have tall people in your family/friends. Some people hate when they have to bend down to look into a tank.