adding mp3 player to car?

i was thinking of adding a mp3 player to my car, i was either thinking ipod mini or creative zen micro, im leaaning toward zen micro now and getting that napster to go and just fill it up with songs, which is hard to beat for getting most any song on there(unless anyone has used it and can say different) although i would like an ipod because of the adapter that will show what song is playing and i can hide the ipod and just use cd player, but no upload of songs with it , gotta buy them old fashion way or used p2p

but i was planing on getting this http://www.crutchfield.com/S-F46N3x...asp?I=130CDRB10

for the zen

or this for ipod http://www.crutchfield.com/S-F46N3x...sp?I=130CDIB100

big price difference too, would the sound quality be the same on both and i would buy it off ebay either one except mp3 player which i will probably get from wally world

probably this black one http://www.crutchfield.com/S-F46N3x...O&display=L#Tab

will it still sound good if i do it like this? i have the little adapter to turn headphone into rca so dont need that, and does anybody do this in their car? and where could i get a holder for one to mount in car?