Matrix CUBE

http://www.head-fi.org/forum/thread/516993/review-matrix-cube-dac
 
That's a link to my extensive review.
 
In summary, the Matrix Cube is a cross between the Cambridge DacMagic and the Musical Fidelity V-DAC. It matches the detail of the DacMagic with the smoothness and musicality of the V-DAC, all for a lower price. And don't forget the built in headphone amp, which is very much on par with the Musical Fidelity V-CAN/V-PSU combo. In my humble opinion this is a best buy right now in the $300 range, and would make a very solid foundation for someone building a system.