The Helm of Command These will be the BiS for barbs and most likely monks due to the rolls of %life, % block, res All and Dex/Vit/Str.
Mempo of Twilight will be a PvPer helmet due to its high percent of cc reduction, % life, and attack speed.
Andariel's Visage is one of the most widely used helmets in the game at the moment. High attack speed and crit chance + chance for a socket, % life, and high base stat.
Tyrael's Might Chest with movement speed (movespeed) increase and damage increase to elites.
Beckon Sail Top chestpiece for Demon hunters due to high Increased Attack Speed (IAS) and crit chance increase. Can roll 0-3 sockets for huge Dexterity bonus.
Tal Rasha's Guardianship IAS on chest and a set bonus of (2) 3% increased fire damage, (3) 3% increased lightning damage, and (4) 3% increased cold damage.
Inna's Glory IAS, movespeed, and crit chance.
Justice Lantern for extra %block.
Natalya's Mark IAS + high base stat rolls and use of Set bonus.
Flavor of Time like OP stated IAS, movespeed, and CC reduction on a neck. PvP neck for sure.
Mara's Kaleidoscope decent tank neck with reduction from melee/ranged.
Storm Shield for the % reduced damage.
Ivory Tower is another decent shield that can be used for its damage reduction and its chance at high % life.
Black Bone Arrows for % damage against elites will make farming quicker for DH.
Dead Man's Legacy is another quiver. This differs from black bone in the fact that it can give % increase to some of DH strongest abilities along with a chance for the highest % attack speed on quiver.
Uhkapian Serpent is BiS for WD due to its chance at max off hand damage, % damage against elites and chance on roll to give % damage to certain WD spells.
The Oculus like the WD mojo this can give specific spell % increase as well as being able to roll high Int and top damage on a source.
String of Ears for the % melee damage reduction.
Boj Anglers Increased attack speed and movespeed with cc reduction. These will be pvp boots in my eyes and can be fitted to any class.
Zunimassa's Journey Increased attack speed and movespeed.
Fire Walkers Reduced melee and movespeed.
Natalya's Soul Reduced melee damage and movespeed.
Lacuni Prowlers These are extremely powerful at the moment for an increase in movespeed to hit that 25% everyone wants and IAS which is a straight damage increase. Even better is these can proc magic properties to make them beneficial to all classes.
The Three Hundredth Spear, The Gidbinn, and Sunkeeper all %MF weapons for you and your Companions.