How is your music ripped? Do you purchase your music online from iTunes or do you buy the CD and rip it losslessly? I do know that the Arcam dock is meant to be one of the best, if a little dated in it's functionality and features now and it probably doesn't charge the latest ipods (My own dock doesn't!). Perhaps Arcam are working on a new one, I don't know. The wadia dock is meant to be one of the best around and the only one that outputs digitally from the ipod bypassing the on board DAC.
I have a couple of ipods but only use it as a mobile listening device with ear phones and never download music. I always buy the CD and rip it to FLAC (lossless)/convert to mp3 for use on my ipod. My music is streamed using a couple of Squeezebox classics in a multi-room setup. I have heard that the Apple equivalent, Airport Express should offer the same levels of sound quality but ultimately it will come down to the bitrate etc. of your music, which is just as important as the equipment being used.
The computer based music forum might turn up some more answers. Unfortunately digital music seems to get spread over the HiFi, WiFi, mp3/mp4 and computer based music forums, which is something that I personally think WHF could look at.