The t5 quad light would be the cheapest most likely. And it will grow most corals you would think of. The Halides will grow anything you want but you have to worry about the heat and the temp of the tank, sometimes you need a chiller ($$$$) and like t5's they will require bulb changes about every year.
Now the led
hanging panels are what alot of people use on this forum, i have 4 different panels running right now myself. lol The pros' are you dont have to worry about heat or bulb replacements, and the electricity used is alot less too. The halides will suck down electricity like crazy and the t5's use an average amount. The only downside to the led
's is the initial cost. Check out ebay, they have the panels that everyone uses and they should be about $120 or so each panel but you would need 2. They can grow anything just like the halides so thats another plus.