Building new system starting with power amp. What would you choose ?

The room we have, is the room we have for most people.

You are right...

I am lucky because i could acoustically transformed my room for my audio system... At no cost at all.... Esthetic dont matter in my audio room ....

But if your audio room is the living room, it is nearly impossible to install at low cost treatament and controls of the room that are cheap.... Esthetic means often costly... i imagine that it is possible anyway in a living room in some case of positive geometry, positive topology, and positive acoustical content materials...

stibi, I agree with you, I would consider Lamm first. Question is which one.
Diablo 300 is a very fine choice if you want transistor amp, and it can easily be found used, there are couple here right now. 

What if someone special gave you your favorite amp as a gift ? You would want to start building the new system from this, right ?
Another thought. Many speakers are actually better than they might seem but they do not perform their best because the amplification is not good enough.
Lamm, Gryphon, Nagra, D'Agostino would work very well with a wide range of speakers. Not sure about Levinson ML-2, besides try to find it, I guess.

The room you have; might not be suitable for the speakers you're considering.  The room might very well be the reason to reconsider a specific speaker for one that will work within it.

That might be another reason to start with the amp. Room might change, speakers might have to be replaced, but your favorite amp will stay.
In my case, I will never have very big room and I listen at moderate levels.

Purifi by VTV at <$1500 or spend a little more and get the NAD  version, giant killers