Which components knocked you out on first listen?

JL F100
JL
F112
JL F213
JL F113
B & W 802D

EgglestonWorks Fontaine speakers - my first, and still current, main speakers. I had auditioned several speakers for my first venture into high end audio. Up until then the speakers (all far cheaper, retail-wise) I heard were nice, and obviously better than my current low enders, but none knocked me out. When I auditioned the Fontaines they knocked me out cold. At that moment I knew I had to have them and begin a pursuit of high end sound.

My wife was pissed at me when I got home with them for blowing my budget, but after setting them up and selecting the "Miss Sarajevo" track on the Passengers CD, she was equally floored and thus quickly forgave me. These speakers really are special.

The NAD 1020 is a pretty decent mid-fi component, yet a direct swap out with the ARC had me amazed at the depth of sound and clarity. This was especially noticeable with complex or classical music, where some of the 1020 rendered muddled, ambiguous content, while the ARC resolved so much better.

Coincident Pure Referance Extremes doubled up
4 Pure Mini Monitors and 4 pure subs
All powered by an 8 watt set no less.
Absolutely blew me away!

For me, knockout power is correlated to the difference of actual performance over anticipated performance. The EMM Labs CDSA knocked me out.