Best digital format (non streaming)

CDs ripped and then played from a hard drive, connected to a dac with an s/pdif converter.  IMHO it would sound better than almost all transports connected to the same dac via coax.

Presto Classical doesn't off DSD but has a huge selection of other HiRes downloads.  HDTT is another site and they off DSD

+1@ @arcticdeth. With the caveat that it’d be a cd transport and separate DAC.
My McIntosh MCT also accepts large capacity usb thumb drives. Helps me play my DSD files that don’t play natively through my Bluesound node. 

I noted down the referenced sites for hi res downloads. I will visit and check out what they have (and cost). Thanks for posting.

I have compared uncompressed FLAC to the WAV file and I can't hear the difference.