This is a copy paste of my own post, but some stuff is altered.
Hc or sc?
Either way, this is my general setup:
Max strafe. Strafe i use instead of multishot, because with strafe, every arrow carries special effect modifiers such as chance to cast amplify damage from atma's scarab. Every arrow also pierces with enough points in pierce and if using razortail, so it is the most effective skill. Auto aim is also time consuming and easier to use.
Max valkyrie.
3-5 points in dodge, avoid, and evade.
3-5 points in pierce.
Max critical strike.
Remainder of points in guided arrow, which is mainly used for bosses.
Gear:
Fortitude, because of the 300% enhanced damage, and chilling armor increases defense. Treachery for poor player's option.
Razortail is the best belt, unless you are looking to survive burning souls, in which case you should use thundergod's vigor and dual wisp projector.
Gloves: Laying of hands set gloves gives 350% enhanced damage to demons, which is a significant boost, and i cannot see how crafted kb gloves can do them justice. Knockback isn't really that useful.
Raven is a good ring, but i've just come to realize, it isn't really necessary. It does increase damage a bit, but look to helmet option. As for rings in general, you should have a wisp projector and use Spirit of wolverine, which increases damage a little bit. Oak sage can be used, but dies far too often. Wolverine spirit seems to fly away from enemies and can take a few hits.
For second ring, you can use whatever you wish. Dwarf star for increased survivability, 12-15 mdr is not a bad thing. Ranged enemies are your biggest fear, especially packs with fana or might aura, multiple shot and extra strong. 1 volley can kill you.
Amulet: Atma's scarab is the best amulet. Amplify damage will be cast very often, and doubles output damage. Cat's eye is a very good amulet, and use it if you wish, but you will miss the doubled damage from atma's scarab.
Helmet: Kira's guardian. You should get as high all res as possible, and socket it with an um rune for more all res. This helmet also gives Cannot be frozen, so you really do not need a raven frost. This is a life saver and highly underestimated.
Boots: War travelers. You can try gore riders for yourself and see which deals more damage, in my experience, war travelers are the best boots.
Weapon: Faith grand matron bow is the best bow. For second place, i choose Eaglehorn, since it has Ignore target's defense. Combined with Atma's scarab and strafe, you will deal big damage. Windforce at third place. It has low attack rating, and slow attack speed, but high damage. I've taken off 1/3 of diablo's health bar with 1 arrow while cursed, in hell mode. Fourth option can be Cliffkiller. Harmony is a great runeword, which will make you run very fast. Almost any unique bow will do the job, but Faith Gmb is the porsche of bows.
Charms: I use mainly resist charms, max damage charms (AR not needed if you have ITD on bow), life, and faster run/walk. Faster hit recovery to hit some breakpoints. Magic find is welcome. 1 gheeds i always carry. I don't necessarily use torch, since i get tired from watching the firewave attack. Annihilus is great, but expensive.
Merc:
The grand setup is: Fortitude, pride and andariel's visage. "Poor" player's option may be shako, reaper's toll and treachery. Other options are vampire gaze, crown of thieves, duriel's shell, shaftstop, insight. With treachery, Fade will be cast almost always, which increases survivability quite a lot. Combined with damage reduction from vampire gaze, he will become tanky.
For softcore, you can be a little more aggressive and place more points in damage skills. For hardcore, you may want to place more points in defensie skills (d/a/e). You also have to play more defensively. Casting Decoy is a standard, i use it all the time, always in every doorway and around any corner. 1 fast boss pack can tear you down in 1 second, with lag spike too, you have no chance to react. Let Decoy be your scapegoat. If there's a pack, throw valkyrie there and start using strafe.
It is possible to not use valkyrie at all, in softcore, saving you lots of points. You must kite a little bit, but it's all up to your play style.
Good luck. Bowzon is the best build of all ^^