I was poking around Drivethru RPG and came across a bunch of West End Games items available for free.
D6 was probably the system my group played the most. Our classic Star Wars campaing carried us through many, many years. Through it we discovered Ghostbusters and later we even converted a bulk of the RIFTS books into D6 once we grew too fustrated with the Palladium rules (which boil down to most MDC, wins). It actually worked quite well.
I've got a real sweet spot for the simplicity of the system and am happy to see that there are still dedicated fans out there keeping it alive.