The Best Pulley
Best Pulley: Perrin
Reasoning: Perrin is the only major manufacturer of lightweight stock diameter pulleys. Though under-driven pulleys aren't a major concern, most people don't want to mess with any possible electrical issues they may cause.
Not entierly correct; Autospeed Performance makes a lightweight stock diameter crank pulley also.(See here)
I don't know if you'd consider them a major manufacturer though...