Jewelry - MR, SSI and over-capped SDI, and +Stamina (not Dex); anything that can't be crafted. With each of these you want complimentary mods.
I sort through all armor with +90 resists, and build some awesome armor for cheap. My sampire uses armor that is cursed, but must be repairable. My archers, mage/mystic and tamer/bard all use cursed and can't be repaired armor and it lasts a long, long time. I have at least one spare armor piece in case it gets lost or broken.
No one else buys these pieces, but they are simply overlooking diamonds in the rough.