Dac suitible for both bookshelf and floorstanding

I'm looking for a DAC (preferebly under $700; can maybe stretch to 1,000) that I can use for my passive florstanding speakers (marantz HLM/PM series) and active bookshelf (focal). I also plan to pick up some studio monitors in the future. I mainly listen from my computer (no soundcard) so I need something that can do USB. Any sugestions would be appreciated.