Depends on your playstyle. I would say the best PvP weapon playstyle (The one that requires the last skill whilst still maintaining a huge level of destruction) is a +15 Rapier with Crystal Magic Weapon on it on a Dark Magic INT build. You don't really have to know what you are doing, just sit behind a shield and poke them at melee range with your rapier for 500 damage per poke, and one-shot them if they go away from you.
But usually Black Knight weapons are great for PvP due to their high damage. But as I usually say; The best PvP weapon is the weapon you best know how to use. In PvP it's 30% equipment, 70% skill imho, so even a naked guy with a dagger can take you down if he plays well.
Think we all have had that happen to us at some point.
And yeah, the pursuers build was on PS3. Currently playing my first faith character on PC. Going to kill Gwyndolin for the Sunlight Blade and the helm.
That shield will block attacks from everything without giving any bucks.
I have a different setup with my char using lighter armor (Pyromancer armor at +9), which is when I fight enemies that are magical users, however, instead of the Artorias Greathshield, I use the Cleansing Shield.