Hardware:

1.  Fish Tank (duh :)  50-75 gallons is ideal for a first time I have run reefs in 10-20 gallon aquariums, but the challenges and maintaneance is greater.  Keep in mind that temperature fluxuations of more than 2 degrees per day is very stressful to the reef and the smaller the body of water the harder it is to control the temperature.

2.  Stand (If home built make sure it is strong enough!)

3.  Hood (Handing or on tank)

4.  2 pumps 

5.  Sump

6.  Skimmer 

7.  Heater  (Make sure you have right size for aquarium.)

8.  Plastic piping and fasteners.  (Lowes, Home Depot etc)

Animals Live Rock:

1.  Live Rock (make sure it is cured, ie make sure there is very little dying things on the rock.  Look for brown slime.  Both of these are bad, go someplace else!)

2.  All plastic wire ties for fasting rock together and masonry drill bit for drilling holes in live rock.

3.  Rubber gloves to wear while handling the live rock.

2)  If you aquarium is going to be drilled, make sure the bulkhead fitting has been placed such that you can attach a pipe on the bottom of the aquarium once it is placed on the stand.

3)  I suggest getting a 2-3 dollar level (bubble circle type)  that you glue to the base of the stand in the sump chamber.  This is an easy way to ensure you have a level stand.  

a)  think about power failures and syphons.  Natural Syphons can be VERY bad things in a sump based reef aquarium.  If you are not careful, a power failure can cause your aquarium to be emptied onto your floor.  50 gallons of water is a BIG mess!!. Here is one way to avoid the syphon problem.  On your water input, make sure that you have two inputs.  A larger for the majority of the water, and a smaller that can be close to the surface.  The smaller will break the syphon in case of a power failure. 

2)  If you have never used the aquarium or any of the components it might be a good idea to fill it with freshwater the first time.  You can then mix the aquarium salt after you have elimintated all the leaks.  (DO NOT PLACE ANY LIVE ROCK, FISH, or other living things in the aquarium until you have filled it, fixed leaks, added salt, and cycled your tank.)  

3)  Some people put the substrate (if any) in before filling the tank.  The plus to putting the sand in before is that you will get less clouding in the water.  The minus is that if you have a big leak. level problem, etc, then you are going to have a big mess to drain the tank and get out all the wet sand.  If you are doing the Jabert method (plenum, screen, and, then screen, and finally fine sand on top, you will have to install the sand first and fill second.