need suggestion for which speaker matchs NAD M2

psb and nad are owned by the same company and i always see them auditioned together--the psb synchrony line is great.

No experience with the M2, (used to own the M3),but Loomisjohnson made a good point. Also you may want to research and call a few NAD dealers and get their take on speaker matches. And, do an internet search; see if you can find if the NAD M2 was at any of the audio shows and the specific speakers NAD paired with the M2 at the shows. (most likely PSB)

Usually it is the other way around - you have picked your speakers and want to know what is the best amp for them. In your case you already have an amp or are committed to it. Since it outputs 250 wpc and has greater than 60 amps of current, I would think you could match just about any speaker available and not worry about driving it. So it becomes a matter of what type of speakers do you prefer?

A warm, laid back sound? A more forward, bright sound? Do you prefer the sound of a soft dome tweeter, metal tweeter, ribbon tweeter, compression horn, etc, etc, etc...
Are you looking for floor standers or monitors? What is your room size? What type of music do you prefer? I would ask myself all these questions, know my answers and start auditiong to find out what is the best speaker for me and not my amp. Again, with the power the M2 puts out, you should have no problem mating it with anything that you decide upon. Good luck on your journey.