Originally posted by Veseljko:

As i understand, every weapon or shield has 3 categories:
BLOCK POWER - This is the base amount of damage you will negate while blocking normally (modified by your blocking skill)
PARRY FORCE - This determines how far enemies will be knocked back when parried
PARRY BONUS - modifies BLOCK POWER by PARRY BONUS when successfully parried attack.

So if you have 10 BLOCK POWER on your weapon and x4 PARRY BONUS, successfully parrying will negate 40 dmg before armor and resistances.

Its like this
And best block armor for parry are from :
Rounded/buckler shield
2 handed weapons ( have a lot of block armor since h&h , my crystal battleaxe can parry 101 of damage with 55 blocking skill , blackmetal atgeir have more)
1handed weapons
Bows ,knives and claws