Litz wire is enamelled copper wire, the type used to wind transformers and coils. It's also used by all of Cardas cable - everything is basically low-guage (thin) magnet wire. Others may also be using such wire for their constructions.
Bud is the guy who 'discovered' the EnABL process, that is used by a lot of satisfied people. Bud is also a pretty solid engineer (proven, not hypothetical). He's basically beefing up the return to provide a more solid ground reference.
The most contentious issue that counters the entire discussion (to me, at least) is that ground is not a concept. In a speaker system, the ground does not "absorb" anything. The electrons travel along both the halves of the cable, so any changes made in one 'half' affect the other equally. So if I use an extra-thick wire for the return to lower the resistance, I affect the electrical properties of the entire path.
I_F had the best post in that thread. I pretty much stopped reading after that