Resolving amps

Another vote for VAC 300.1. However, I think that this is a sum of the system as a whole and not necessarily something that an amp will bring to the table, on its own.

If you are attempting to run Magnepans, you should look at the Magnepan threads. They are a bit of a special case.

McCormack DNA 500 was the best at resolution I've had.

Maggies like a lot of power. I would choose between the following:

McCormack DNA-500
Modwright KWA-150
Clayton Audio M100 or M200 class A amps

IME Maggies are easy to drive if the amp is alright with the load. A lot of tube amps can do the job other than this. So if you want a tube amp, often you can use a set of ZEROs http://www.zeroimpedance.com and do quite well. Sixty to eighty watts does seem to be a good minimum in a lot of rooms though.

Windell Diller of Magnaplanar has told me on several occasions that the best he has ever heard the 20.1s sound was with a set of 200-watt tube amplifiers.