Recommend tube amp for $3.5K used

I'm going to make one significant upgrade this spring, and am considering a used tube amp in the not to exceed $3.5K range. I'm not sure if I should go with a moderate/high powered push-pull (Berning ZH 270 or various VAC, ARC, etc) or a lower powered SET amp (Art Audio, Cary, etc...). Musical tastes range from rock (Paul Westerberg, Pete Yorn, Springsteen) to Dianna Krall, Lyle Lovett, Jack Johnson, some classical, etcetera.

I see a lot of people bi-amping... but is that really necessary with highly efficient speakers (95dB @ 8 ohms)?

My speakers (Silverline Sonata II's) and Joule Electra LA 150 preamp are keepers, so recommendations should have good synergy with these components.

I want good dynamics, solid bass, air, soundstage, detail, while remaining fatigue-free. Yes... I know I'm asking for the moon.