The Hifiman HM-801 looks like an old portable cassette player, but apparently it might just beat out most music players in sound quality. At least that's what CNET though when they had a listen. They even found it worth $US790.
The Hifiman was designed with audiophiles in mind, so it comes with features such as user removable headphone amplifier circuitboard/module, a Burr-Brown PCM1704U digital-to-analogue converter, and Burr-Brown OPA627 Op-Amp. Instead of a hard drive or flash memory, the player uses 32GB SDHC - meaning that capacity is only as limited as your tolerance for carrying around spare SD cards.
Many of us might not care about some of the finer details of the Hifiman, but what we should care about is this: It sounds amazing. According to CNET, this particular player is one of the very few which will actually take full advantage of everything your high-end headphones are capable of. [CNET]