I haven't listened critically to an iPod and don't own one. However, I own and have traveled extensively with a Creative Zen Touch and an iRiver iHP-120. Both these players support uncompressed WAV.
I use the Zen to drive Etymotics ER-4P's and with a Headroom Total Airhead portable amp to drive Sennheiser HD-650's. The iHP-120 drives both transducers directly. Of these two, the iHP-120 has better sound but it is still not audiophile quality.
Recently I purchased a Overture limited edition transportable DAC from Headroom.com. It's about the size of the iHP-120. The Overture has an optical (Toslink) input and this can be driven with the optical line out from the iHP-120. The Overture DAC is very good. If you put the Overture's output into a Ray Samuels SR-71 portable amp (about the size of an iPod) driving Ultimate Ear UE-10 Pros, Senn 650's or whatever your flavor of earphone is, you get a three box solution that is probably going to do about the best that can be done in the transportable department until someone (Headroom?) comes out with something more integrated.
I use the Zen to drive Etymotics ER-4P's and with a Headroom Total Airhead portable amp to drive Sennheiser HD-650's. The iHP-120 drives both transducers directly. Of these two, the iHP-120 has better sound but it is still not audiophile quality.
Recently I purchased a Overture limited edition transportable DAC from Headroom.com. It's about the size of the iHP-120. The Overture has an optical (Toslink) input and this can be driven with the optical line out from the iHP-120. The Overture DAC is very good. If you put the Overture's output into a Ray Samuels SR-71 portable amp (about the size of an iPod) driving Ultimate Ear UE-10 Pros, Senn 650's or whatever your flavor of earphone is, you get a three box solution that is probably going to do about the best that can be done in the transportable department until someone (Headroom?) comes out with something more integrated.