I'm fairly new to all of this really but it seems from my reading that you need to match your headphones to your amp really? And your own taste? Surely it's subjective?
A friend of mine swears by his Pro iCAN (amp) and Pro iDSD (DAC/streamer) stack from iFi audio - he would say that for his ears, this the Pro iCAN with the Pro iDSD is the best he's ever heard. I heard it and thought it was pretty awesome but I know I've also heard other things I like.