#2
With 4 conductor you can do things like coil split, parallel wiring and such, but cannot do so with a 2 wire.
Agile AL3000
Douglas WRL90
SX SR1 STD Plus
J&D Strat
Squier Tele
Sammick TR2
Douglas Draco
Peavey JSX
Bugera V5
TWANGED VJ
#4
Just get the 4-conductor one. It doesn't matter if you don't want to or know what to do with them right now, but it gives you the option of re-wiring it in the future should you want to.