Extend the concept of Magic Find / Gold Find to all loot types: +% chance to find Runes, Gems, jewelry, elixirs, armor, melee weapons, ranged weapons...
Damage reflection, based on damage type. Eg. Fire damage reflection, ranged damage reflection...
Some type of affix that makes killing sprees easier (allowed time without a kill increased).
Affixes that give attack / armor bonuses while on a killing spree.
Affixes that give elixir / potion effect boosts.
Vision related affixes (more than just +light radius) highlighting things like: mobs, treasure containers, traps, breakable environment.
Gambling gear: increase the chances of gambling rares / sets / uniques, decreases the cost of gambling, %chance for a gamble to be free...
Charismatic gear: decreases vendor costs, increases quality of "gossip" tips, increases gold / item based quest rewards given by NPC's...
Sage / lore gear: automatic identification of loot (no identification scrolls needed)... could be a scaled system (based on treasure class or blue/yellow/green/gold...).
Levitation gear. Eg. walk / float across the broken bridge in the gameplay video.
Mana / fury shield gear: takes a percentage of damage from mana / fury reserves instead of health.
Stoneskin gear: decreases run/walk and attack speed, but with a huge armor boost.
Frightening gear: chance for mobs to flee when near (great for ranged attack characters, bad for melee types).
%chance for slain monster to have an (elemental) AoE explosion on death (eg. frost nova, poison nova...).
%chance to blind target for x seconds
%chance to pierce all defenses (armor / resists) on critical strike
%chance to root target in place (mob gets sticky feet, but attacks within its range still possible).
%chance to transform target into (insert mob type here). Eg. hit a zombie and it transforms into a skeleton.
Barb (Fury) specific:
"Short Temper" gear, amplifying fury gain from combat.
"Grudge" gear, decreasing fury drain when not in combat.
"Idle Rage", fury regeneration when not in combat (this one would have to be exceedingly rare, perhaps on a complete elite Set).
%change to corrode armor / weapon (decrease enemy defense / weapon based attack damage)
%chance for a slain monster corpse to turn into a mob magnet for x seconds
%chance for a slain monster to be revived as a minion for x seconds
%chance for target to panic (with panic = running in circles, attacking anything in range at random... no coherent flee or attack strategy).
%change for target to go berserk (zero defense, but with attack bonuses... kind of a catch-22)
%chance to curse target (with a variety of curses)