Music Servers VS Excellent Transports?

I am new to this area and was wondering if someone can provide a brief explanation as to the differences between using:

Slim Devices Transporter
Modright's version of Slim Devices Transporter
Wavelength Audio USB DAC
Empirical Audio's products (PaveCar, Turbo, etc.)

My digital front end is an ARC CD2. I thought that upgrading to another stand alone CDP or Transport/DAC combo was the only way to go for audiophile quality sound until I stumbled onto this forum.

I have been reading this forum incessantly for the last couple of days trying to come up to speed on this alternative. From what I surmize, these three company's seem to be offering different implementations of the same basic solution, which is having a Hard Drive based PC front end. What I am trying to understand is how they differ from one another and what the pro's/con's might be.

I will also be attending CES/THE Show in January and would welcome any information on "shoot outs" or A-B demo's that are being scheduled in this arena.

Ckorody, thank you for your in depth and informative answer to my question. I think I get it now.

Audioengr, thanks for the schedule and layout for these setups at CES/THE Show. I will be seeing you in your room as well as the others.

Splaskin, thanks for your additional insight on the wavlength Crimson.

Davemitchell, thanks for the heads up on Linn. I will make it a point to see them as well. Do you know where there will be shoing this technology?