USB's come a long way since the dark daze ... I actually prefer the sound to what's available from my optical and coaxial feeds. All about how a specific machine processes it I guess. My box has RealTek HD audio, which is supposed to be decent, but the USB just sounds fuller and sweeter, even at lower resolutions. Allegedly, all S/PDIF is created equal, but that's not always the case, and my DAC has the Tenor usb chipset which gets rave reviews. USB also wins for ease of use as it's mostly plug and play nowadays.
Here's the USB expansion card I got to cure the system hiccups ... $25 at NewEgg ...
VANTEC 4-Port SuperSpeed USB 3.0 PCIe Host Card Model UGT-PC341
Nice choice on the case. LianLi is some nice solid stuff. Purty too. You'll be surprised at the weight of the case. Only thing you got to watch for is some of their cases require a proprietary power supply, so it's best to check when ordering.
Didja go with the solid state drive for system software? Mine was less than a buck a gigabyte with zero noise and heat. Big change from my old Seagate Barracuda, which was fast, but loud. The SSD runs rings around it in any category, including speed.
SAMSUNG 840 Series MZ-7TD120BW 2.5" 120GB SATA III Internal Solid State Drive (SSD)
Tiny little thing too. I just velcroed it down to the baseplate on my ATX case. Kit includes a 3.5" adapter, so they'll also fit in a standard hard drive slot.