Your last sentence is telling. Right now at this moment, you don't have very many options at all beyond 80GB of storage, let alone considering all of the other criteria you listed. Aside from iPod Classic, I'm not aware of any relatively small form factor players with storage space beyond 80GB, and from my own experience I'd hardly consider the Classic a great-sounding device.
It wouldn't surprise me if the next-gen Touch pushes its storage cap up to 128GB, with the Zune HD (or its generational successor) following shortly thereafter. The same could be said for an uprated device from Creative, with perhaps Samsung, Sony and Cowon right behind since the 64GB cap will already have been the standard for a year going into this fall. But right now for large cap devices, all that's out in the wild from any of the majors is the iPod Classic and the big footprint of the Archos Internet Tablet, neither of which are noted as being that phenomenal at feeding out superb SQ.
Hey there, I have been attempting to decide on a next gen Mp3 Player for my music addiction and am at a bit of an impasse on what to purchase. Audio quality is a must of course(flac compatible would be nice), and a built in or easily attachable/non-bulky head phone amp is needed for serious output. Size is also a large(no pun intended) concern. My 80gb Zune is nearly at the bursting point. Recommendations?