Im in the middle re-insulating the attic in my home. All the insulation has been removed and I have about 80% of the attic floor cleaned. Before I move on with insulating I want to do something about these hvac ducts.

http://imgur.com/gallery/e1gK04q

The main duct is rectangular rigid and about 50 foot in length. All the branches are rigid as well but circular. Most aren't no more that 4-6 feet in length. They are currently wrapped in what looks like fiberglass batts thats intended for walls and not hvac use. Its also hanging and falling in places and the exposed metal, of course, sweats where the hot attic air hits the chilled metal. I replaced two branches last summer with the newer flexible insulated ducts because i noticed a water stain on the attic hatch cover and that was currently the easiest route. I also fixed two branches that were leaking air into the attic at the joint where they connect to the main.

So my current question is what would be the best way to go about fixing this issue?

One of my friends who used to work in the hvac industry just recommended changing out the rigid duct and going with insulated flex duct. It actually sounds more appealing than wrapping 50 plus feet of duct in a hot attic in Louisiana.

Other than replacing the rigid with insulated flex I've came across duct wrap insulation that looks like fiberglass with a radiant barrier attached to it and I've also seen fiberglass boards. Im sure i can handle whatever route but I'm just looking for a little more input before deciding which route to take.