Another peice of helpful advice that I learned along the way: get your QT going a few weeks before you are ready to add any fish to your DT. I had to do an emergency quarantine and when i moved the fish to the QT many suffered and died because it had to cycle just like any new tank. I got torn between letting them stay in the DT that had been exposed to ich by a new fish and letting them move to a QT where I could medicate them. Neither was a good option!
When you set up your DT, toss a sponge from a sponge filter into your sump. I've just decided to keep one in there any time I don't have a QT going. Let it sit there until you are ready to start stocking then get the QT going, assemble the sponge filter and make sure it cycles before you buy anything. If you follow a quatantine procedure that most recommend, DON'T put anything ( rock, sponges, filters, decorations) from the QT into your DT. The copper from the medications will ruin your live rock in the DT.