I had a hex, never buy one again. Too much vertical area and not enough horizontal area for the fish to hang out in. Plus you really need to match your pump well to the tank, I ****ed up and had a pump that was rated for the gallonage but it was still too powerful and created a whirlpool effect in the tank, I killed the fish by overexertion having to swim constantly. It took about a day to kill them off so by the time I realized when I got home from school, it was too late.
If it's your first tank, i'd avoid saltwater too unless you have enough time/dedication to really take care of it. Freshwater is more easily maintained and less hassle too.
I'd also recommend getting yourself a second tank to use temp to house the fish when you're cleaning/maintaining the primary tank.
-8/21/2007 RIP Grandma
-pessimum genus inimicorum laudantes: flatterers are the worst type of enemies