Best Loudspeakers for Rich Timbre?

"Piano can either sound plain and two dimensional, or it comes alive as you get to hear all the tones and micro tones."

I think you mean OVERTONES, not MICRO TONES. Unless you really like listening to an out of tune honky-tonk piano.

Ribbons and planars are very good, but take some getting used to, because of the lack of distortion that cone drivers have.

They definitely sound less "loud", which I imagine comes from the improved transparency and reduced distortions. Now that I am used to them, cones drivers sound very coloured in sound.

They do have a more realistic warmth, if the recording is "warm" sounding.

Who is Rich Timbre?

ProAcs are getting a few mentions. I've only heard the Future One's many years ago but they did sound good to me on the end of some Marantz gear. It was at a London show and Ken Ishiwata was there.  

The Future One's were slightly pyramid shaped floorstanders with an open back behind the midrange unit! 

Some of the people with me thought they sounded fabulous, the best in show. I was in such a hurry to hear everything else that I didn't stay too long to listen to this strange looking expensive speaker from this unknown brand!!

There are several things about the Magnepan x.7 series that supersede all the dogma about previous maggies--grainy, lack of low level detail, hard to drive, etc

That describes just a few of the reasons I unloaded my 1.7is, however, I'll admit they're one of the best at their price point.