the advantage that a walkman has over an ipod is tunable tape compression. if you've been making tapes for a long time, and you make lots of mixes on certain brands of tape you can get your touch together on hitting things to tape in a certain way that brings out the bass and squishes the cymbals in a really cool way. i haven't been able to replicate this even in a DAW. one can get fairly close but it's a simulation of something easily done on tape. also, like if you watch a movie, they use filters to adjust the color palette in certain ways. most films aren't just a "picture" of a scene. the colors are processed to create a thematic unity therewith. a really badass filter to run music through is just a slight amount of surface noise or tape hiss. this is why many hip hop records and experimental guys will cut in a sample of a run out groove off a vinyl record. it adds a very flattering filter to the music. one which a person making a cassette can control. {tape type, machine type, how hard the tape is hit} if you ever go to a live show and you see the lights on the stage, they'll pump some smoke out there to give the light something to bounce off of. filter.
i'm a big believer in using the right tool for a job. if you want to take a zillion songs and pack lightly, of course the ipod. if you really want to juke, you're going to need some cassettes, a walkman, and some badass headphones.
i should also mention pause button editing, and controlling how tight the gaps are. this can be done digitally in a DAW, but the basic itunes software does not allow this type of creative listening as far as i know.