I have a UA-1EX plugged into my benchmark DAC1.

The UA-1EX is a ok sounding but in reality I only used it as a way of getting a digital signal into my DAC1.

Since you say 'best' I personally think that setup is best as the UA-1EX provides a stable digital out, while the DAC1 provices a jitter free output. However the ~$1100 price tag might put you off.

Quote:
I have much music stored in uncompressed format on my computer. I woudl like to buy an interface that takes this digital data and converts it the best way to analog and then hooks up to my (state of the art) amp.

Cheapest way is the M-Audio Transit USB, costing around $80. Analog output is okay, but you can feed the S/PDIF optical output to an outboard DAC like the Benchmark DAC-1 or Musical Fidelity X-DAV v3.

John Atkinson
Editor, Stereophile

Wavelength Brick

and there are higher end versions.

USB DACs