Yep, I agree with unmeg, don't listen to the guy selling you the tank. From what I've seen there are two types. 1-The ones who don't know shit but try to convince you they do. And 2-The ones who do know what they're doing but will still fill your head with shit to make a sale.

If you're going to set up a reef invest in a few good books. The Reef Aquarium Vol. 1 and 2 (Delbeck and Sprung) and Aquarium Corals (Borneman) are good choices. They'll give you a ton of info.

One other thing, I see you mentioned the tank you're interested in having a stand and a canopy. Unless the canopy is custom made for a reef tank it will probably be worthless. Lights for reef tanks put out a ton of heat (think pot grow lights) so you'll need a canopy that allows the lights to be at least 3-4" (more if your using metal halides) over the water and you'll need some ventelation like computer fans. Otherwise you'll have problems keeping your tank cool enough.