Cloth covered, PVC or Teflon™
insulated (not
shielded) wire shouldn't technically make a difference as far as noise or sound quality is concerned. PVC is relatively inexpensive, widely available, fairly durable and easy to service and work with, which I would guess is the main reason that it is so prevalent. For these sort of builds people seem to prefer a solid core hookup wire because it retains it's bends fairly well. I have always felt that stranded hookup wire is less prone to microphonic type noise than solid core, but that's just my opinion. A stranded hookup wire gives you a level of forgiveness... That is, if a solid wire breaks your done, whereas a stranded wire will usually fail a strand at a time and you may get years more service out of the joint.
Teflon insulated wire is always silver plated (as opposed to the nickel plating found on most other hookup wire types) due to the high temperature of extruding the Teflon material over the wire. Nickel plating would burn off essentially during the extrusion process. Teflon is expensive, hard to service (usually stripped thermally), and some types are very "springy" and won't hold a shape, except for the shape of the spool that they came on (wire memory). Some do hold a form very well which is what I used on the V6 Rackmount.
I won't get into the "this wire sounds better than that wire debate", although there may be some truth to it as far silver plated wire is concerned. If I were building a Deluxe I think I would go with tradition and use the cloth covered pushback wire

Just one man's opinion!!!
Joe G