Your single favorite component

Of all the pieces of your system you now own or have owned in the past, is there any one piece you could say is your absolute favorite piece of equipment? 

I don't know if I have an answer to my own question - I enjoy various pieces of equipment for different reasons. A turntable I've owned for 18 years, a 40 year old tuner, an amp I built myself, all in some way are pretty special to me. And so on! 
and on second thought I have lots of favorite components. I really like my modded Acoustat 1100 speakers and the two Sumo Andromeda IIA's that drive them bi-wired on custom cable.  Not to miss the crowd is a Radio X modified Sansui tuner and Magnum Dynalab Signal Sleuth and half mast whip.  Sony SACD which is killa on red book rounds out the list... 
PrimaLuna Dialogue HP Integrated Amp.  No contest.  This thing changed everything.
I've had many but my current "love" is a newly acquired Esoteric SA-50 CD/SACD player.
Quad PA One headphone/pre amp which I re tubbed with Shuguang black bottle treasure cv-181s

The best 12 hundred English pounds I ever spent

Now all I need to do is save up for those Audeze LCD 2s
I would have to say that my BEL 1001 MK5 (made in 2007) is the top component in my system.