Yes you can, and it's in this area where the iPod excels, whereas differences in sound quality in players will be less obvious - I have Primare kit at home but listen to most of my music on a nano with Sennheiser CX300s, and am never fretting about any limitations in the ipod's sound....
Edit - whether or not you value the additional functionality of the Cowon is a different matter - SD card slot, for example.....
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