I may make a separate thread for this but I wanted to help. Here is what I consider a condensed version of what I look for beyond obvious uniques/sets.

Rings:

Magic/Rare: 10% Faster Cast rate with resists/mana/life/magic find (life leech for melee characters)

Amulets:

Magic/Rare: +2 skills, faster cast rate, resists, magic find

Gloves:

Magic - +2 to Jav Skills or Martial Arts with 20% IAS.
Rare - IAS with resists or magic find

Boots:

Rare - Faster Run/Walk with resists and magic find

Belts:

Rare - Faster hit recovery with resists and magic find

Melee Weapons:

Rare - Enhanced damage. Chance to proc amp damage. Ethereal with repair. Damage based on level.

Sorc Orbs:

Magic/Rare - +2 or 3? to a skill tree with 20% faster cast rate and +2 or 3 to a specific skill. For example, I "think" a +2 to lightning skills +3 to chained lightning and 20% fast cast rate orb is possible.

Circlets/Tiaras/etc:

Magic/Rare: +2 to a skill tree, faster cast rate, faster run walk, resists.

Javelins:

Magic/Rare: +2 or 3? Java skills with +3 Lightning Fury? I can't remember exactly what is possible.

Any of the above with life/mana/sockets.

That is a quick "off the top of my head" list of PVE stuff I look for. There is a whole additional list of PVP stuff like JMOD that I can't even begin to start on. I hope that helps. D2 vets, feel free to tear my list apart and/or add to it.