Which of your component purchases was "magical"?

Or better -- "What component purchase had you digging out all of your favorite recordings, late into the night, just to relish in a new level of reproduction?"

We have all heard, read & sometimes experienced this occasional audio "revelation" from time to time. My question is which rare component/purchase did this for you?

(BTW - one of my earliest and most memorable was the first time I heard my Well Tempered TurnTable, after coming off a mid-fi table, some years ago...;>)