Lets talk ipod lod's and materials.

Uh I'm not 100% on the materials of LOD's making a huge difference, most of them just look really nice and the nice ones I consider a luxury. Just being real upfront with ya...

If we're talking about cables in general, there is no best between silver and copper, people establish what flavor they like and go from there.

Copper: Warm, darker treble, warm mids, bass is relatively unaffected

SPC: Silver plated copper, middle ground between copper and silver

Silver: So many grades of this determine the outcome that in my experience it hasn't been standardized yet. Silver is known to be bright, treble extends further and is more prominent, mids have a lot more clarity, in SOME scenarios, bass gets light and stays that way, or increases with burn-in, or in some cases even gets better. Right now with the stuff I've been using it's really hard to establish what it does, I generally use it for everything except for reference headphones like K701's, HD800's, LCD-2's, and DT880's.

Crystal: ??? (It's basically the depleted uranium of cables, not a whole lot of people have access to it, it should be excellent from the specs and what it's made of, but hardly anybody knows what it sounds like)

In terms of insulation, cotton is an OK dielectric, but the fraying over time, difficulty to braid, and relatively high cost compared to PTFE teflon which is a better dielectric make it somewhat impractical for audio purposes.

In terms of manufacturers, I have a couple favorites on here, DHC, Zombie_X Amateur Cables, Moon Audio, and Apuresound are some of them that I like alot because each one has a product that they build the best.

basically i do not think this question can be answered in isolation, the way i see it each material has its ways it interacts with specific setups. copper by itself is not going to make your rig sound warm, silver by itself is not going to make your rig sound detailed. personally i favour copper for most of my own cables, as well as piccolino in selected positions.

that being said the only wire in my portable rig these days is internal apart from the cable on my jh13 (26awg TWCu copper), oh and the mini lemo coax, which is vhaudio upocc 75r mini coax with spc shield and very thin solid copper internal conductor; although i will probably change this to belden mini 75r copper coax as its thinner and more flexible. all the internal signal wiring is piccolino, power wiring is a mix of 16awg silver foil for the battery centre tap/star ground tap, 16awg neotech upocc and vhaudio 18awg upocc in foamed teflon for other wiring. digital hookups are all micro bnc cables.

I certain ipod/iphone lod accessories require small authentication chips to work properly. Ben Heck has a tutorial for splicing in a chip for one of his hacks.