Hi -
I got one of the first Audiences ever and it rocks - even makes a difference with our junker Sony Boombox. That IMHO makes it a real deal tweak.
Monster also has a cable and we use one of theirs (actually just their RCA pair to mini) into our Nakamichi head unit on the boat (12v automobile unit) Also sounds very good. (Rest of the system is an Alpine 200w 4 channel amp and Energy speakers - not like my big rig but hey its a boat)
BTW It is unclear to me if the iPod can utilize Apple Lossless, WAV or AIFF encoding. In non empirical tests we did determine that the newer iPods sound a lot better than the original 5Mb unit I started with.
best,
ck