Confused With Options To Obtain BestQuality iTunes

I have been reading a lot these days and still confused on the plethora of options available in hooking up a computer based digital system and the pros and cons to each and every selection. I am quite new in this so please bear with me.

I have friends who stream wireless music(Itunes) via an Apple Airport Express that supported this idea and do know many folks are using this setup in their homes. Others who are into Logitech stuff advocated the Squeezebox Classic and Touch. However, another group who uses top-flight gears in their systems(upper range MBL and Revels) advised that wireless degrades sound quality, and the best option is to hook it all up with wires.

Suggested options to play Itunes in WAV or AIFF format are as follows.

1) iTunes in 1TB/2TB External Hard Drive => Mac Mini/Macbook => DAC (iPad to control music selection)

2) iTunes in 1TB/2TB External Hard Drive => Logitech Squeezebox Classic/Touch => DAC (iPad to control music selection)

3) iTunes in 1TB/2TB External Hard Drive => PC => Apple Airport Express => wireless => DAC (iPad to control music selection)

4) iTunes in 1TB/2TB External Hard Drives => wireless => Apple TV => DAC

Out of the four options above, is it a general consensus that option 1 will yield the best sound reproduction from iTunes followed by option 2? Will options 3 and 4 come close to options 1 and 2? Are there any other alternatives to do all this?

Basically my priority is to use an iPad to control playback from iTunes stored in 1TB/2TB external hard drives WITHOUT using a Mac/PC. Apple Airport Express and Apple TV were said to degrade sound quality. What other cost-efficient options do I have?

An advice would be most appreciated.