Please, don't turn this into a flame war.You might post, "Well, Diamond can be used more then iron items, so Diamond!"Well, If you ask me, Iron, is better then Diamonds. Why do I say this? Iron can be used for more stuff, then Diamond. As far as I know,Diamond can be used for1.Diamond blocks2.Armour3.Pickaxes4.Axes5.Shovels6.Hoes7.Swords8.Jukeboxes9.Enchantment tableIron, can be used for1.Iron blocks2.Armour3.Pickaxes4.Axes5.Shovels6.Hoes7.Swords8.Buckets9.Sears10.Flint and steel11Iron bar12.Minecart13.Steel door14.Cauldron15.Compass16 Both pistons11.Normal rail track and Detector trackI might be missing some stuff from both lists, so if I am, please let me know.So, if you ask me, Iron is just more useful, then Diamond. Its also easier to find.