While cost isn't a major concern, I also don't want to waste money knowing my only source will be MOG, which streams at 320k, on a Macbook Pro. I have no interest in having a debate about the quality of the source or a compressed vs lossless battle. This is simply a result of a specific need in a specific environment.
My initial thought was to go with something like the Dragonfly, which is also a headphone amp, as opposed to a more traditional outboard USB DAC + head amp, which may or may not be too much given that the source will never exceed 320k. BTW, I'm also looking for headphones for this - and only this - setup, an am open to any style (in-, on-, over-ear).