what digital cables for my dac?

It seems that most of the analysis of digital cable length is based on theoretical levels of reflections in cables. These usually assume some horrible mismatch between transport and dac, or a digital cable improperly terminated. If we are talking about a properly designed and terminated cable, then other factors besides reflections come into play; such as bandwidth attenuation caused by inductance and capacitance values that increase with length.
If we're comparing apples to apples, quality cable in different lengths; then I suspect that much of the praise for longer lengths is due to personal sonic preferences.
I used to use the standard 1m lengths in my system, but then I discovered that my setup prefers .5m. It's more open, and less smeared and colored in the midrange and treble.
Maybe the best bet would be to buy some decent cable at various lengths, and see what your system 'likes' best? Then you could use that length in further listening tests with other models of cable.
Okay, so that's maybe not the most practical option, but what about this hobby is 'practical'? :)

Take a serious look at the one made my Bluemarbleaudio.

http://www.bluemarbleaudio.com/

This guy makes some awesome cables.

Sterevox. This is the designer who created the Illuminati digital cable, which was something of an industry standard for many years in the 90's. He's back and with a digital cable for well under $200. This is an easy decision.

Drubin
Sterevox. This is the designer who created the Illuminati digital cable, which was something of an industry standard for many years in the 90's. He's back and with a digital cable for well under $200. This is an easy decision.

Agreed, it's an outstanding cable for the money. I think Galen Carol audio has them at a decent price too. Try gcaudio.com.

Jack Dotson, there doesn't seem to be very much at that site. The nav buttons don't load anything--no cables, no systems, no speakers... maybe it's my browser.