My list considers PvM only (and what I like about the item).
Sampire items:
Mace and Shield Glasses or Prismastic Lenses (for the HLD plus stats/damage increase)
Cameo (slayer, SSI, DI, etc) - If I can ever get more than one, I'll exclusively use these
Despicable Quiver or Ranger's Cloak (HCI, resist, dex or SSI)
Gloves of Feudal Grip (DI, stats, regens)
Animated Legs of Insane Tinker (SSI, DI, dex)
Britches of Warding (Stam inc, HCI, LMC)
Conjurer's Garb (DCI, MR)
Crimson Cincture or Ozymandias' Obi (HPI, dex or stam inc, str)
Corgul's Sash (DCI, Stam inc) - Honestly, it's mostly because it's the only dexer sash item
Mage items:
Scholar's Halo (SDI, FC 1, LMC, resists) - If I can ever get one. The drop rate on new artifacts is too low, but that's another discussion
Dr. Spector's Lenses (SDI and stats)
Pendant of the Magi (overcapped LRC, LMC, SDI)
Protector of the Battle Mage (SDI, stats)
Cuffs of the Archmage (SDI, MR 4)
Compassion's Eye (SDI, LRC, Luck)
Jumu's Sacred Hide (SDI, FCR, resist) - I believe this is the only mage-ish item for the back still obtainable. The DI on it is used for dexers, but the mix is kinda gross.
Tangle - Really the only mage focused apron item
Mana Phasing Orb - Again, the only mage focused talisman item with multiple mods. The Clean-up Brit items are ok if you rely on the skill bonus
Hephaestus (spell channeling, FC 1 (2), LMC, resist)
Vesper Museum Chaos Shield (spell channeling, FC 1 (2), FCR 2)
Hawkwind's Robe (overcapped LMC, MR)
For me, I look for items that have a clear purpose. It needs to be clearly for a mage, warrior, tamer, bard, etc. I think a better way of looking at it is; is this item meant for a spell caster or someone swinging a weapon. When items have a mix of both kinds of stats, it can become really hard to use it. Most of the time, those items are discarded or sit in a chest "just in case" and never get used. The random loot from spawn gives so many of these items, that having a solid artifact to build around really helps.
Some item slots only have one or a few items that can be used there, so they're used by default. I love SDI, so anything with SDI is used by default by my mage.