Best Cable Option: Streamer to DAC

"Jitter is no longer an issue with most modern DAC’s or streamers that now has internal clocks to combat jitter."

This is totally incorrect as virtually any DAC will provide better SQ if it is fed a cleaner digital signal.

There are many fine renderers or digital bridges that will aid in providing a better digital stream to the DAC than the one coming out of a PC, for example. Some of them terminate with a s/pdif, some with USB and others with I2S. Users have found quality sound with each of these types. The price ranges for these are quite large. Some of the highest value devices use s/pdif as output.

My DAC will accept an I2S input and, theoretically, it should be best. But I did some research on the issue to find, to my satisfaction, that any such device at a reasonable price did not perform as well as the unit I finally ended up with that has a USB output.

kijanki

Nyquist applies only to continuous waves, so intermittent (music) 22kHz signal would have sidebands ...

It isn't clear what you mean here. Music is a "continuous" wave.

+1 @mgrif104 . Great post!

This is great information and I appreciate the thoughtful responses. I have experimented with my system connections, but never tried USB, thinking it would be inherently noisy. Noted definite improvement of SPDIF over Toslink. I use Transparent Reference or Ref XL cabling exclusively. I am getting Aesthetix Romulus DAC upgraded from Signature to Eclipse at this moment so I want to extract everything it can offer when I get it back. 
Intrigued by the idea of DDC between streamer & DAC. Will be the subject of more research. The obvious consensus is USB, and my takeaway is to get one that is well made and shielded. The notion that SPDIF has timing encoded with data was new to me vs USB only data. Never really thought of it in those terms. 
This is how the forum is supposed to work. Thank you all

99% of the back catalogue is redbook. Presently the best connection is mainly dependent on the quality of the interface implementation between streamer and DAC. Increasingly, the engineers spend their efforts predominantly on USB. There are however still instances where specific proprietary solutuons (e.g. I2S) outperform.