Paradigm Ref Studio 80's - Minimum Tube Power?

I am looking at going to a tube amplifier (or tube monoblocks) to power a set of Paradigm Reference Studio 80's. Specs on the speakers say that suitable amp power range is 15-250W. What would be a "good" minimum power rating for a tube amp to appropriately drive these speakers? More speaker specs:

Design: 3-driver, 2 1/2-way bass reflex
Crossover: 3rd order electro/acoustic at 1.8kHz - 2nd order electro-acoustic at 400Hz
High-Frequency Driver: one 25mm PAL pure-aluminum dome, ferro-fluid cooled
Bass/Midrange Driver: one 215mm MLP mica-polymer cone, AVS diecast heatsink chassis
Bass Driver(s): one 215mm filled polypropylene cones, AVS diecast heatsink chassis
Low Frequency Extension: 27Hz(DIN)
Frequency Response:
On Axis 0 degrees: +/-2dB from 40Hz-22kHz
Off Axis 30 degrees: +/-2dB from 40Hz-20kHz
Sensitivity-Room/Anechoic: 92dB/89dB
Suitable Amplifier Power Range: 15-250 watts
Maximum Input Power: 180 watts
Impedance: 6 ohms
Well aside from the speaker's efficiency, other factors include how loud you like to listen, how large and how well damped your listening room is, how far back you sit, and even what type of music you listen to.

For instance, you'll clip on solo piano at a much lower average SPL than on rock music. Piano is extremely demanding of peak amplifier power.

Paradigm's recommendation of 15 watts minimum looks reasonable to me. That would theoretically give you peaks in the lower to mid 90's at 10 feet away in a medium-reverberant room. If possible go with a tube amp, as they can be driven into clipping much farther than a solid state amp can before the distortion becomes audible because they "soft clip", producing fewer high-order harmonics (which is what the ear objects to). In practice, a tube amp will play maybe 3 dB louder than a solid state amp of the same power before you notice the distortion.

I second more to add or say.
Right on... thanks for the inputs guys. Now I just have to decide whether I want to go with an integrated, a pre-amp/amp combo, or mono blocks... of course i don't have an unlimited budget so I'll keep my eyes open for a good deal here.

Thanks again.