how much power

I once believed the"you can never have too much power" credo. With exposure to the high quality low watt amps I discovered superior sound and better music reproduction(more natural and real i.e. less hifi or canned).
As long as there`s sufficient power for a given speakerload, the simpler less complex amps usually out perform. YMMV.

Speakers with a minimalist xover do not require very much power to sound good. Many of these exotic multi way speakers have very complex xovers that require mucho dinero amplifiers with enough current to power a small village due to the xovers gobbling up half the power before reaching the drivers. YMMV

Charles1dad,
By all means low-wattage amp can't reproduce real volumes of let's say acoustic upright bass even in the small room. High-efficiency low-wattage friendly speakers can't have sufficient bottom-end performance and lower efficiency full range speakers can't be driven by a few watts of power.

Marakanetz,
I agree with your 2nd point ( I clearly said amp has to match the speaker load demand-requirements).
Your first point I simply disagree with based on direct listening encounters over the years. A low power amp if matched with appropriate speaker(load and efficiency) will provide full and relistic bass(I know I`m not the only either).
If your experiences have been different no big deal I understand, but I know what I`ve heard. We`ll just have to agree to disagree that`s all.
Best Regards,

I'm running a dual transformer YBA amp which is 50 watts into my 86db Vandersteens, not a problem. I have a 200 watt Rotel and except for overall bass the YBA wins hands down. It's a small room and I listen to jazz mostly.