"Broken" twink items

[nuuki]

Excluding haste, fungi, and epics.. what are some twink items that made you go wow I can't believe I was playing my character without this? And why?

First one that comes to mind is the Necro/SK Circlet of Shadows (instant invis), but I don't know if this is quite on the almost broken level.

Curious to see what other classes have available to them and what you feel makes them so great.