On weapon xx-xx poison over time - try to get as max as possible. It gets better with lvls. Also there is rw for that, so keep and eye on dagger base with poison.
Belt - also can get add on with poison over time dmg. For example one of the set belts has good values.
Rings, amulet - max resists, resists based on char level.
Shield - block and atacker takes xx damages.
Rest of gear - best you can get.
p.s.: update on Hell walkthrough - Hell Diablo boss has this nasty habit of constantly casting iron maiden. The curse lasts forever and boss heals fast. So currently i am farming act 4 when bored. Modder is not responding in other forum, no idea about patch timing/updates.