What kind of metal is best for roof flashing?

Copper is a good metal for flashing because it is strong, malleable, and durable, but really any flat sheet of metal will do the trick

Aluminum would last the longest being it doesn't rust out like metal.

Sheet lead is most preferred by roof tilers as it has proven to be long lasting, cost effective and readily available. I am interested to know what sort of roof you are putting down as there are different options for different types of roofs..

I have found that if you aren't sure about something it pays to give a call to one of the companies that manufacture the flashings, they will be able to answer just about any question that you have. Not all roofing suppliers are manufacturers, these guys definetely are and make similar products to the Colorbond, and Lysaght products.

Flashing No1 Roofing Building Supplies

Copper is a great metal for roofing and to make gutters with. I have never seen anything so strong and long lasting. The uniquely convenient advantage that copper has is its flexibility. You can bend copper easier than most metals I've seen. Although it can bend, it's still a durable metal that can stand all forms of weather. http://www.kfcroofing.com.au/catalog/index.php?main_page=index&cPath=24

Sheet lead is most malleable softer to use &shape with lead beater,copper &aluminium can also be used but more difficult to shape around chimneys ,valleys and gutters etc.