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
sinner
Don't forget the Apogee Mini-DAC at $650 or less used, or $900 and under (used) with USB. Warmer sounding than the Benchmark, better highs than the Music Hall.
Havana. Replaced a more expensive Bel Canto with the Havana and very happy with it.
So I stopped in my local HiFi dealer yesterday and they let me listen to the Wavelength Audio Proton (apparently they are local here in Cincinnati), and I have to say I was pretty blown away I didn't realize a digital source could sound so good (it was being piped through a 300 watt McIntosh tube amp and some pretty pricey speakers but still)!

The salesman was making a big deal about the Proton operating in asynchronous USB mode, which from my understanding bypasses the computers processing all together. With a price tag of $900 it gets up in the range of some of the others mentioned above, I was just wondering what you all thought of this DAC and also wondered how much of a difference the Asynchronous USB mode actually makes? My only gripe about the Proton is that USB is it's only input option, it would be nice to have some more options but it's not a deal breaker for me.