What is the best 2-way Magnepan ever made ?

Probably any of the 2-way Maggies could be nominated for this. I would likely vote for the MG 1.6 also but, frankly the MG 12 is a superb sounding speaker too. There is a good reason the Absolute Sound considers the Magnepan 2-way speakers probably the best bargains in audio, ever. It would be difficult to argue with them on this topic.

If you have the money, I would recommend the 1.6. If you're going after home theater only, then the MG 12's with a sub.

I like the newer Maggies. The older ones are fine sounding speakers but, the newer ones sound more coherent and, seem on average to be more even balanced. These are generalized comments though, as I have not compared them side by side.