Assuming this a piece you'll want to keep for several years, as opposed to changing it in a couple of years, I would recommend along the lines of what Hgeifman posted above. DACs are not a mature technology and as such they are still evolving pretty fast. In two years you can expect current DACs to be surpassed by much. Amps are mature, on the other hand.
I suggest you look at iFi products for the DAC section. In fact, in their case it would be DAC and volume control. For $500 you get a good unit, and you can pair it with an amp of your liking for a grand.