What has been your most satisfying component?

Actually, I have two "landmark" components:
Philips MFB 544 active loudspeaker, 3 way, 3 inbuilt amplifiers, 10 inch woofer. Tonally correct, dynamic soundprint with ability to convery body and presence to music. No more hassle with matching speakers, amps and cables.
Apogee Rosetta AD/DA with firewire card. It is a wonderful dac able to compete with the best with added functionality to connection to PC, which would more than enough to justify its price alone. But its inbuilt AD converter and firewire card made possible to record onto my computer live classical music concerts broadcasted by local FM station. Direct live transmissions have something special feeling of live music and ability to convey the "being there" feeling.

Audioquest Doubled Bi- Wired Volcano S/C added so much resolution, they not only upped the anti they changed the game.

A marantz 8B with m-o valve kt77's and rca clear tops in the driver stages. 16+ years now. I go to sea for a living, that's how my tubes last so long. Looking back, I paid $65 ea. for those outputs - wow, those were the days.

I rarely buy new equipment....DAC...yes but I seem to be able to upgrade my equipment. So I have found I get more enjoyment doing that than creating a revolving door. I have had my speakers since 1980 and my Accuphase since 1975. The VAC Rennaissance is legendary...I just bought a pair of mono blocks. I started with NBS and just upgrade as funds allow. A good system that works for me.

I bought a demo McCormack DNA225 and had Steve McCormack do his Platinum and ARC2 upgrades/mods (whatever you want to call it). The amp has exceptional sonics and has been very dependable (knock on wood!).
Sometimes think about a tube amp but would keep the DNA225 even if I got one.
Plus, Smc Audio was a pleasure to deal with.