"As a master of the dark arts, you wield the powers of life and death necessary to restore the Balance! Necromancers are powerful spell casters who lay waste to their enemies using curses and reanimation—along with an obedient cadre of pets. This new class employs a controlled gameplay style using the raw materials of life: blood and bone."
The Necromancer is a class that feels at home in Diablo III. It was my most played class in Diablo II and I was expecting it to be a near clone of the Diablo II class and I was surprised that it plays differently but feels very similar in tone to the original. My current Necromancer character "DeathsDoor" has the dual Scythe as his main attack(it sends out two Scythes that hit all enemies in front of him) and a long ranged bone spear alternate attack that takes up mana. This bone spear is a good powered attack for taking down enemies at a distance and travels through all enemies in it's path. That said the main fun of my current Necromancer build is my massive army of Skeletons, Corpse Explosion, the Flesh Golem and Bone Armor.
When you play as the Necromancer whenever you kill an enemy a corpse drops on the ground. The Necromancer has many abilities to use corpses and one that's my favorite is Corpse Explosion. This allows a crazy chain reaction where you start exploding enemies in a chain to take down a huge mob. The only downside to sinking most of your abilities into corpse attacks is that if you don't have any corpses available you can't do much. Corpse explosion works well for huge mobs but not bosses so having good alt abilities here is useful.
Another cool ability is Bone Armor which is activated when you select it over a group of enemies and it yanks out their bones and you wear them as armor for a time. It's a fun and totally gross ability that fits the Necromancers theme well.
I haven't leveled my Necromancer to max yet but already have had a blast just taking it as far as I have. The Necromancer is a very fun addition to Diablo III and one I am very interested in playing more of when it launches this summer. With that, I still wonder what the future of Diablo III is and I hope they add another campaign to the base game as I really enjoyed the last one in Reaper of Souls. That said, the Necromancer update should be well worth checking out and if you want to jump back in to Diablo III it might be a good time to do it.