Welcome to RAG!
Before you do anything else get yourself several good books on state of the are SW reef systems and read them. You are about to spend a lot of money on equipment and livestock. Find out what you really need and what will work.
You are going to need to figure out what you want to maintain in the tank. This determines what equipment you need.
Don't be afraid to ask about what you intend to purchase. There is a lot of junk equipment out there. There are also a lot of fish and other livestock being sold that doesn't belong in your tank, you need to be aware of what they are so you don't buy them.
Always buy top quality equipment. It's cheaper in the long run. Be prepared to replace everything. What is used for SW systems is often much different.
Also see this thread -
http://www.reefaquariumguide.com/for...ad.php?t=42443
Lastly, there are a lot of bad LFSs out there. Don't trust any of them until they prove otherwise.