I havent' tried them, but I hear that the folks at airhead are one of the best sources for high quality headphone sound. They recommend the Panasonic SL-CT470 ($89.00) as the best sounding player. They manufacture their own line of headphone amplifiers to boost the power and improve the sonics. They sell a small battery powered unit that matches the portable CD player.

http://www.headphone.com/EditorialPr...uyingStuff.asp