First, let me clarify that I do not believe that there is any one 'best' of anything in this hobby. The following response is what I personally consider to be the best to my ears, and in my experiences thus far.
On the more expensive side of town, I'd say either the Karan Acoustics KA I-180 (solid state), or the Jadis DA50RC (tube).
On the more expensive side of town, I'd say either the Karan Acoustics KA I-180 (solid state), or the Jadis DA50RC (tube).