Glynn,
I just made the switch to a modified mac mini (modified by mach2 music) and use it with PureMusic with my Tranquility SE dac and it is many, many notches higher than even a tweaked Asus eee box and using foobar 2000 in kernel streaming with the incredible AQVox usb driver. In fact, the modified mac mini is easly the best transport I've ever heard, even on dacs other than the Tranquility SE, and the stock 2010 unibody mini is really great with just a few software tweaks you can do yourself. You can also use an iPhone or iPod Touch with the iTunes remote app to control a headless mini both with and without PureMusic. PureMusic is a significantly better sounding playback engine than quicktime, which is what iTunes uses for playback.
HTH,
Jim
Jim Rebman -- recovering audiophile
Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).
s.e.x. 2.1 under construction. Want list: Stereomour II
All ICs homemade (speaker and power next)