There are two things you really need to look at:
1. solid-core conductor
2. awg size of conductor
In my experience, the larger awg solid-core conductors just perform better (up to a point). The problem is that most cable manufacturers do not tell you how they make their cable. I have heard good things about Black Cat, but I have never tried them. I make all my own digital cables at this point.
The one cable I can recommend in the Nordost Heimdall 2. At $1149 retail for 2 meter (find a good dealer). It's a large 20awg silver-plated solid-core copper with its dual mono-filament insulation (presents more air around the actual wire, which is less restrictive). This cable has very full and powerful bass with an excellent depth in the sound. However, it's not the best for ultra high frequency resolution and air. It depends on what you are looking for.
There are tons of digital cables made only to 24awg or 21awg conductors. Even 21awg is somewhat lacking in bass (but better than the 24awg or smaller conductors).