Hello people, since 4.1 has arrived, huge improvements are made for summoner necros. This guide will include skill/attribute build and itemization. Items are subject to change. THIS IS A HUGE END-GAME BUILD WITH ONLY 1 LIFE DUE IRON GOLEMS DYING AFTER CHARACTER IS DEAD. I doubt there will be a better summoner necromancer though.

Attributes:

Since necros got a new skill called "lich form" which gives tons of health with percentage, we should keep our vitality as high as possible. That's why I'd prefer going for STR bug with Enigma and charms. All attributes go directly to vitality. If you prefer perfect block over raw HP, go for it. But as a summoner with lots of meatshields, I don't think that's a right approach.

Skills:

20 pts into: Skeleton Mastery, Raise Skeleton, Raise Skeleton Archer, Skeletal Lich and Summon Mastery
1 pt into: Revive, all golem types, Teeth, Corpse Explosion, Amplify Damage

Itemization:

Helm: Shrieking Lich with +1 Golem Enchant (Stat priority = Golem count > All res > Magic res)
Necklace: Diablo's Rebirth (Skeletal Power > Unholy Might > % Vitality)
Armor: Enigma RW Mage Plate with Superior %15 Enchanted Defense and x2 +1 Golem Enchant
Rings: Stone of Jordan x2
Weapon: Goka Uln with +1 Golem Enchant [other two enchants can be used for cannot be frozen and whatever you like] (+5 to Skeletal Lich > Skeleton Mastery > Skeleton Archer > Vitality)
Shield: Warmonger with +1 Golem Enchant (Aura > FCR > All Res if you are close to FCR breakpoint of helmet)
Boots: Death's Advance with +1 to Necromancer Skills enchant (Aura > DR > EDef)
Gloves: Purifying Flame with +1 to Necromancer Skills enchant ( Aura > Absorb)

Switch: CTA & Corrupted Stormshield

Follower Gear: Act 1 Cold Bowyer Rogue

Helm: Focus RW Shako with Superior %15 Enchanted Defense, Damage Reduction Enchant and optional FHR Enchant (All Res > Aura)
Chest: Guardian Angel with x2 DR Enchants and optional CBF / FHR Enchants
Weapon: Faith RW Hydra Bow with x2 DR Enchants (Bow type is your preference, Aura > All)

This setup seems very pricy, ain't it? It is NOT over though. We'll have 8 Iron Golems with very expensive but great items to finish our setup.

Golem Items:

All weapons written below will have maximum amount of Ber runes and Crushing Blow enchants

Frostmourne
Thunderfury
Stormspire / Schaeffer's Hammer / Stormslash
Sshha's Primordial Fang
Insight Runeword
Bramble Runeword
Infinity Runeword
Last Wish Runeword

In total with golems and mercenary we'll have these auras: Physical Pierce (25), Conviction (15), Meditation (18), Might (35), Thorns (40), Holy Freeze (30), Fanaticism (20), Concentration (25)

Disclaimer: PLEASE DON'T YELL AT ME IF YOU DIE AND LOSE ALL THOSE IRON GOLEMS. I'VE SENT A PM TO GAME IF HE CAN MAKE GOLEMS PERMANENT FOR A FUN EXPERIENCE. WE MAY HAVE A HIGH VARIETY OF BUILDS THIS WAY.

Any suggestions on Iron Golem choices are welcome. Meditation Aura is not useless, we'll be spamming many skills with zero + energy from attributes.