Have a MusicHall 25.3 Dac...

building a HTPC and deciding whether or not to add an upgraded soundcard to the PC or just use the onboard soundcard built into the motherboard. Is there any point of feeding the DAC w a soundcard like the SoundBlaster X-Fi or will this be pointless/redundant?

Ie, will connecting to the DAC via USB, and not passing through a premium soundcard accomplish the same sound?
I assume that you are planning to use the Optical out on the soundcard? If the soundcard already has a digital out you could do this, but if you had to buy another soundcard I would just use the USB cable. I own a musichall and love the sound through the USB.