Well, if you're looking to use your BD for PVP then arena armour is essential for the high resilience and critical it gives, as well as decent amounts of HP. Don't forget you don't have to use all of the pieces, mixing with armour from other sets (such as Killing Whisper or Divine Defence) can often be beneficial as you can balance out your stats to make a good all-round BD. To get a set bonus you need at least 2 pieces of the set, 4 pieces for the second bonus.
As far as enchantments go, I would say use resilience runes on the belt, chestplate and boots, use penetration on rings, parry on cloak and depending on your critical and accuracy, choose whichever is lowest to put on amulet (Balancing your stats is good!). If you have under 3k Health put HP runes on your amulet. If you have only 5 energy regeneration then put it on your belt.
When deciding what weapons to use it really depends on what you prefer. If you want to hit fast then use daggers. Of course the drawback is less damage. Most 1h swords have parry so if you want to be strong vs. melee, and maintain good damage and DPS, use swords. Axes have awesome damage but hit the slowest. Axes usually have penetration which cuts through defence. Most BDs nowadays use axes.
Finally, light armour and daggers aren't commonly used on BD, however, I've seen pro BDs who use these such as Hamstring; high amped light armour with high amped daggers give awesome stats and are great in PVP. Hope I helped a little