DAC recommendations?

I have only recently gotten in to vinyl and while I love the sound, I currently only have about 10 records so the majority of my listening is digital still. I have about 300 GB of lossless FLAC, which is how I do the majority of my listening (currently I have this hooked up via optical to a cheap home theater surround system).

I currently have a Rega Mira 3 amp, Rega P2 and a pair of Monitor Audio RS6's and was contemplating picking up an external DAC. FLAC will be played from a MacBook pro (is it better to use the optical output, USB, or firewire for a connection?).

I've read several good reviews on the Music Hall 25.2 DAC, but I'm not sure if my current set up is good enough to enjoy the benefits of $600 DAC... I'm also intrigued by the Jolida mini DAC which seems to have gotten pretty favorable reviews for being just over $100. I'm open to any suggestions but I probably won't be doing any speaker or amp upgrades in the near future so keep that in mind.

Any info would be greatly appreciated.

Thanks