a 30 lbs sword. You need either a slow heavy weapon or a light very fast weapon. There are two factors in that equation, usually you cannot have them both. Just like heavy people cant punch very fast but a lighter more suple person can send you a 90mph punch. :)

I think heavy weapons should be hard to parry and easy to dodge. Light weapons should be easy to parry but very tough to dodge. Shield block would be equally good for both kinds of weapons.