Let's face it, Followers aren't what they used to be in Diablo 2. In Diablo 3 they are a lot weaker but there are things you can do to make them more useful, especially with the buffs Followers are getting in patch 1.0.5 (PTR patch notes here).
The following guide will take a look at which Legendary items you can equip on each Follower, along with Legendary items that can be used for all Followers. As these items are generally very expensive, this guide assumes you have a reasonable amount of gold. If you don't, check out Diablo 3 Gold Secrets.
Note: The majority of the items you will see listed below are the patch 1.0.4 version. If an item is labeled with [Legacy], that means it is the pre-patch 1.0.4 version. Also, all prices shown are based on the European Auction House.
Kormac the Templar
The religious warrior and elite from the Order of the Templars. Here is how you can make Kormac more effective:
Preferably rolled with the strength affix, this weapon will be of great use to your Templar. Not only do you get 20% of the Magic Find value added to your character's, but it also has good damage. When buying this weapon one should keep in mind that any Magic Find and Gold Find inherited from Followers will NOT go past the 300% cap.
Price Range: (3.7 mil - 10 mil)
A very inexpensive item that has multiple Crowd Control effects on it. With the buff the CC system is getting in patch 1.0.4, the usefulness of this weapon will go up twofold. One would be smart to invest while the price is still cheap.
Price Range: (180 k - 1.2 mil)
Good damage with life regeneration that also has a chance to Smite. Smite is basically a lightning bolt that does about half of your weapon damage which also has a chance to stun. This weapon works best when rolled with the strength affix.
Price Range: (300 k - 90 mil)
Another inexpensive weapon that has an amazing proc on it. The "Chance to summon angelic assistance" does just what it says, it summons a temporary angel to help you. The proc chance is about 20% so it should practically spawn every fight. The angel lasts about 20 seconds and doesn't do a lot of damage, but can act as a good distraction. If you want your Follower to spawn more followers, get this sword!
Price Range: (65 k - 20 mil)
Good chance to freeze plus a proc that pushes away undead monsters. The proc works in an AOE fashion and pushes away all monsters around your Templar, but it doesn't proc very often. This video showcases how it works very well.
Price Range: (80 k - 10 mil)
While the many class specific affixes found on this shield are useless to your Templar, the proc effect does wonders. It works exactly like the Shielding affix found on monsters by making your Templar immune to damage and movement speed debuffs for a short period of time.
Price Range: (6 k - 100 k)
Lyndon the Scoundrel
Hailing from Kingsport, here is how you can make this former Thieves Guild member more powerful:
Note: To get the most out of these weapons it is recommended you use his Multishot ability, which effectively triples all proc chances.
Even though this weapon is low level, it is still one of the best things you can buy for your Follower. Not only does it have guaranteed cold damage (which slows down anything it hits by default), but it also has a high chance to pierce enemies and a good chance to freeze. With this wonder in hand, Lyndon will be freezing monsters all over the place!
Price Range: (30 k - 3 mil)
Another good Crowd Control weapon. When possible try looking for one with a Stun and Bleed chance for maximum efficiency, which by the way, is still dirt cheap. As an added bonus, this weapon is really good at trapping Treasure Goblins!
Price Range: (45 k - 200 k)
50% chance to knockback speaks for itself, but this weapon can be made even better by giving it cold damage. Since the cold damage affix doesn't roll on this weapon your only option is to get a cold damage ring (using the Puzzle Ring [Legacy] for example) or amulet.
Price Range: (300 k - 2.5 mil)
Has average stats but a very good proc ability. Every time this weapon procs a big ball of acid is thrown at the monster that damages everyone walking over it.
Price Range: (40 k - 1.5 mil)
Eirena the Enchantress
The last surviving member of the ancient Hand of the Prophet sisterhood, here is how to make your spell casting Follower better:
Note: To maximize the proc chance on the following weapons it is recommend that you use her Forceful Push and Erosion abilities, as these also have a chance to proc.
This weapon is the bomb when it comes to Eirena. The bases stats are pretty good and become even better if the intelligence affix is rolled, but the real gem is the proc effect. Similar to how the Skycutter sword works for the Templar, this one summons a Demon that is also chained (ala Fire Chains affix) to your Follower. The Demon does good damage especially if the monsters also get caught in the chains and lasts about 20 seconds. The proc chance is pretty high (probably 20% like Skycutter) too, making this a very effective (albeit expensive) weapon.
Price Range: (1.5 mil - 50 mil)
This weapon looks very good on paper, but according to this thread it is bugged. The charm effect (which causes monsters to fight for you temporarily) only seems to work when using basic attacks. Considering how cheap these things are it might be viable for you to buy one anyway and wait until it is fixed.
Price Range: (50 k - 300 k)
Has a guaranteed socket and a maximum of 35% Gold Find/Magic Find. Very good if you need a little boost for treasure farming!
Price Range: (145 k - 3 mil)
Besides the high damage and guaranteed socket, this weapon does wonders if it rolls a bleed affix. The bleed effect will proc and stack from the Enchantress's Erosion ability, making it a must when using this weapon.
Price Range: (3.5 mil - 17 mil)
Follower-Independent Items
Below is a list of items that can be equipped on all followers:
Hope you guys found this guide useful. If you need some cash to gear out your Followers I suggest you check out Diablo 3 Gold Secrets.