The new Canterbury logo is already in this thread, plus on a couple of people's sigs. Having a look in the Bulldogs section would also be an idea.
As for the Knights logo, I think their strength is in their image. The knight helmet with the flowing red thing on top is a recognisable image of the Newcastle Knights. The Knights have just updated their logo (twice) instead of a complete overhaul. This is the way to go in my opinion. Whether they add a shield shape to the background or not, I suppose we'll find out in about 8 years!