Three systems come to mind...
1) Wisdom Audio Adrenaline Rush series speakers, powered by Jeff Rowland 300 series monoblock amps and Synergy pre, with a Wadia 861 as the source. This was the most incredible system: smooth, yet detailed and exciting at the same time; fantastic extension on both ends. This was the mosy dynamic and transparent system I've ever heard. WOW! That's the only thing I can think of to describe the experience. I just stood there with my mouth hanging open.
2) B&W Nautilus 802's, powered by a Conrad-Johnson tupe amp (I can't remember whether it was the CAV-50 or MV-55 at this point), with a C-J PV-10 pre, and using a Rotel RCD-991 or Rega turntable/Koetsu combo. This system was just plain lush. It was warm, and smooooth, and I recall just melting into a puddle of mush while listening to this rig. The bass wasn't as tight as I'd ultimately like, but who could complain with all that liquid warmth surrounding you?
3) Magnepan MG-20.1 speakers, powered by monster Mark Levinson No. 33 monoblocks and a ML 32 Reference pre, using a Mark Levinson 390S Compact Disk Processor. I felt like crying it was so good. This system made me stop thinking about the gear, and just want to listen to album after album. I forgot to listen to specific parts and instruments on my test disks, and just submerged in the music. Perfect... or as close to it as I'll ever hear. Not the most dynamic... not the lowest bass or highest highs, not the most transparent... just musical, lifelike, emotional.