Ok, first off the cheapest way and most effecient way is to go with Rapid LED Home Page
for most of the things you need. As for the heatsink go with www.Heatsinkusa.com
they are based in michigan and will most likely give you a better price.
Here is a list of must have materials.
36 Leds if you want the whiter look, 48 if you want the bluer look. Go with the Ultra Premium LED DIY Kit with Dimmable Drivers version they are the best and can offer a great dusk to dawn effect.
The leds combo should look like this if you have 36 LEDS 18Royal Blue, 12Cool White and 6warm white
the white will get you closer to the red spectrum or a more 14k or less look but will provide better growth for corals and is exactly what I have on 1 of the two heatsinks I have above my tank.
Here is what lighting would look like with 36leds using that ratio of RB-CW-WW
If you want a bluer look than mine then you can always add more blue leds to the kit, as for spotlighting I have none what so ever do to using 60deg optic lenses and the certain placement of the leds height and spacing on the heatsink.
2 rolls of 10 gauge wire electrical wire found at an auto store or hardware etc. The wire they provide many have found to be incredibly short to make longer connections.
go with 36/48 60 degree lenses to provide a better par
rating for your tank as it is considered a deeper one.
DDC-01 PWM Controller for controlling lighting and dimming
since your tank is square I would go with 1 10''X23'' heatsink placed atlest 6 to 8 inches above the water
You will need 2 Fans to cool this off I would go with 100mm+ fans and a 12V AC adapter to power them go to newegg.com to get them they are called kingwin I think and they are $10 per heatsink.
If you do not have the tools needed for this project you will need a soldering gun, electrical solder, possibly a drill to drill the actual heatsink like I have to place the fans upon it
Accordian Tubing for the electrical wire to go into to protect from the water
Electrical Tape and lots of it
and that should do ya, how you hang it above your tank is up to you and this is based off of your 60g cube which I assume is the one you are setting back up.