I just got my 555BE running. I'm using a masscool ball bearing cooler. I think the fan is 80, 90, or 92 mm (forgot, but it's large), and it's not loud. It's really easy to install. It should be enough. But then I'm not oc'ing.
I don't know that the Scythe Samurai ZZ is good though, because it's an unmodified sleeve bearing. Those may not last that long.