State of the Source: Server, computer....or what?

There has been a lot of discussion here about the impact of having the best possible DAC for digital playback, from a long-runnning thread on Lampizator to the current thread where member Mattnshilp has been trying out a variety of DAC's in order to select what sounds best to him, but what constitutes the best sounding digital source?

So the questions for this thread are, what digital source sounds best to you and why? What features do you like in the manufactured music servers? And, can the sound quality from a well sorted-out Mac mini or CAPS style computer/server, with linear power supply, SSD, and the associated ability to use a variety of music players, upsampling options, memory play, and EQ, compare favorably with the manufactured server options that use preloaded programs or, are the differences primarily related to the manufactured options being easier to use than a computer, which requires the user to load and maintain the programs used?