I've done many experiments with 1.10 beta, and the necro with all the new improved poison and all is still shit in Act 5 Hell. For PvP, he will kick ass though.

Now, after trying dozens of different builds, the character that performs the best is a Throw Barb...he easily made it to Act 5 Hell Baal, while others can barely get through Bloody Foothills in hell.

Get dual Lacerators (unique Winged Axe) and you can have an effective 14k damage with Amp and Deadly/Critical strike for each axe. If double-throw hits a target twice, you can double that damage. Any of the other unique harpoons are great too, but I like the winged axes...

EDIT: Doh, this is mantralord, i keep forgetting to log off my sister's account.