iPod docking station - Belkin vs Wadia vs Arcam

Price range and what CDP are you currently using?

Last years RMAF I heard a demo which compared an ipod on an apple docking station to a reasonably good CDP on a nice sounding system (don't remember the components, but a Pathos integrated was involved) and I was surprised at the quality of the docking station. The guys doing the demo said the quality is much worse when you take the ipod's headphones out. Using the docking station bypasses the ipod's volume control, which is a significant improvement.

The Wadia unit does not require a DAC

I spoke with the Wadia folks for a while at RMAF, the unit hijacks the digital stream [i]before[/i] it gets to the Wolfson DAC in the iPod, then outputs it via a digital interface to an external DAC.

You have 3 options.
1. Wadia with an external dac--perhaps the best route--very impressive but depends on your dac--though can be used in analog mode
2. Red Wine Audio iMod -- see 6moons review -- only for generation 4 and 5 iPods
3. basic analogue iPod dock by Apple (best of the type), Belkin, Kensington etc
I've heard all 3 and definitely prefer the Wadia.

You might want to look for this information on headfi as there are a large number of folks that use such things at that site.