Becky,
What I'm reading here is there is no "Correct" flow for any tank. What mostly needs to influence your choice, is what you PLAN on keeping in your tank.
For instance;
Sea Anemone's enjoy a Medium to Low Flow, and don't appreciate being tossed around in a High Flow area much at all. In higher flow, they don't open as large, and may even continuously wander or even hide under and behind rocks, which deprives them of the expensive lighting you've provided that they also need to thrive.
SPS's are filter feeders, and have hundreds to thousands of little mouths to feed (their polyps), and the higher the water movement around those little mouths the more food they are able to filter from the water column, the happier they are.
Sand beds, while being a lovely white bottom for our colorful reefs, tend to be very small particles which can easily be stirred up by direct flow into them. This may cause much more cloudy water. If we desire the higher flow, then we need to think about having this flow coming from near the bottom, and pointing mainly upwards to help keep this "Sand Storm" effect from happening.
Bare Bottom tanks, while not quite as aesthetically pleasing to some as the white sand, doesn't have the "Sand Storm" effect, and having a higher flow helps any detritus from hiding in corners, allowing it to be exported more readily.
What does all this REALLY mean for you?
Look around… Decide what you want in this tank you own… Learn what water conditions those things “Thrive†best in, and compare them to one another. You may find you enjoy mostly SPS’s… so the higher flow the better. You may find your most favorite thing out there is a Pulsing Xenia… and then will want to ensure a medium to low flow rate to get the full enjoyment of its pulsing.
The more you know, the happier you AND your tank inhabitants will be!
Ed