I was hoping to get more into a portable setup with my HFI-780s, and I'm always on the lookout for a new challenge, so I was wondering which portable amps would be best to build? I've done little electronics work, but I'm far from slow, and have a father who's quite competent with these things...

It seems I'm stuck as to deciding between two paths. Having been wading through hundreds of reviews over the last week or so, I've narrowed my headphone-purchasing options down to two separate paths: buying Denon AH-D2000s with a decent portable amp, or buying ATH-M50s and using the cost-savings...