Hi threadstarter,
have you tried the new Sony NW A800 Walkman?. I compared it with Samsung K3, and i choose NW A800. Have been enjoying music since then. The bass seems to be packing more punch...
My frens whom audited my Sony NW A800 is impressed with the sound quality. (they are using ipod nano)
Sticking to ur choices, Iriver / Samsung / Cowon.
Cowon has my vote