I know it would cost a hell of a lot of coin, but if you got the axeblock, spearblock and hammerblock enchantments on your armour, would you have damage reduction 5 that could not be negated by anything?
Go with Adamantium armor. That way you will get damage reduction against nearly everything.
Listen up maggots, Mr. Popo's 'bout to teach you the pecking order.
It goes you, the dirt, the worms inside of the dirt, Popo's stool, Kami, then Popo.
~Mr. Popo, Dragonball Z Abridged
Don't go with Adamantium Armour: it's heavy, expensive and provides poor DR. DR 3/- isn't going to save your bacon, since a few big hits are a greater threat than a lot of small hits.