According to the product page of the Creative Sound Blaster X-Fi USB DAC, it is capable of using hi-fi headphones up to 330Ω. So for the best possible quality, i'd suggest to get the
Beyerdynamic DT 770 Pro 250 Ohm (Over-Ear) with 250Ω. Also to note what i read from an article i read (sorry can't find it anymore) it is not advised to use it with headphones below 60Ω or very high impedance over the mentioned 330Ω proposed by the manufacturer.
Product page X-Fi:
https://en.creative.com/p...