I prefer barebottom because you can have more flow usually.
The bottom of my tank glass is completely covered with coraline, I think it looks good!! If I had it to do over again, I would have put down starboard, just to protect the glass.
But anyway, sand is also cool because there are some fish that need a sandbed to thrive.
i think the more flow thing is a valid point.
many SPS do better in turbulent water. i think that much can be said for a sand bed as well.
i went with a shallow bed to cover all the bases. you can have a good flow in your tank and still have sand.
so it might be beast to know what oyu plan on having when you are up and going... will there be many SPS corals or will it be more of a soft coral tank? do you want to keep corals that are fond of a sandy bottom?
IMO a 2-3 inch sand bed is asking for trouble. better to go with 1/2 inch,because all your going for is looks any ways.I had a 2 inch sand bed,and when I went BB my tank just look's better.