Int. amp...most dynamic, full and smooth $3,000

I love the Conrad Johnson CAV50 and it fits you criteria very well.

For tube, I second the Prima Luna recommendation, and would add a couple others:

Musical Fidelity Nu Vista
Sim i-5
Plinius 9200
Pathos TT
Bel Canto Seti 40

I could go on, but that's a good start.

Have fun

One of my long time favorites which is able to be naturally musical or "just right" sounding, would be Aronov LS-960I. For rock and pop there is splendid bass reproduction that really shows the complexity of good acoustic or electric bass playing, as well as showing what a great drummer can accomplish.
Mine is currently used in similar sized room with Duntech monitors of similar specs. When the recording is dynamic you feel the energy fill the room, but when the expressive singer-songwriters do their thing the chills are there, too.

Would also give my nod to the PrologueII/Prima Luna.

The Cary SLI-80 Signature is stunningly good. Replaced my Pass X 2.5 Preamp and Pass X-250 Amp with it with no regrets. Highly recommended!