Since I built my music server 2 or 3 years ago I've tried a number of USB cables and am always struck by how much they affect the sound. I have two servers now; even though both my NAD M51 and Eastern Electric Minimax Plus DACs have asynch USB inputs, I found I prefer the sound using the Musical Fidelity VLink192 spdif converters, so the USB feeds the MF devices and AES/EBU cables (Wireworld Gold Starlight 7) feed the DACs.
The cheap give away cables I used when I set up my first server sound gritty and flat, definitely inferior to the Sony 9100/modwright signature player I had been using. I was a bit worried that the server option was not going to be viable sonically at this point.
Moving to an Audioquest Carbon was a definite step up, and when I moved to the AQ Coffee the sound matched or exceeded the Sony player. I replaced the Coffee with a Mapleshade USB, which surprised me with a nice, smooth, non-digital sound that I liked very well. More recently, a Black Cat Silverstar USB also gave me the smooth sound I liked, but with more extension on the extremes. The result was a very high quality sound, but I noted that my system still lacked the ambience and spaciousness that I was hearing from really good vinyl setups.
I got a good price on a Wireworld Platinum Starlight (aka Platinum Starlight 6) cable, and with that the ambience, separation and "blackness" between the instruments improved greatly. The images opened up and spread out wide and deep from my Daedalus DA-RMA V2 speakers. It was exactly what I felt I was missing. The Wireworld was just much more 3-d and the sense of space is greatly enhanced. In my system I'm feeling that I'm finally hearing what the recordings offer. It does not sound quite "like" vinyl, but I'm now feeling that I'm not missing some important musical information.
Much more $ than the others (of course!), but now that I've heard how a really good USB cable compares in my system, there's no going back for me. At $600/meter list, the value proposition is a bit stretched, but at 1/2 price this cable is a bit of a bargain for me, offering substantial benefits in my hi-rez system. Are there better cables out there? I suppose so, but I'm very pleased with what I'm hearing.