Barbarian equipment

Barbarian gear is mostly pretty simple -- A big bag full of weapons, and a few potions in case things go wrong.

Armor
Barbarians are able to wear either light armor or medium armor. But by mid-level, in order to achieve a useful armor class the barbarian would have to sacrifice DPS.

As a result, most barbarians ignore armor class and pick their based on its secondary effects. Fearsome armor is a common choice, as it will help keep secondary mobs off you while you are pounding on your chosen target. Robes are also a common choice since they can be found with greater elemental resistance or other desirable effects like fortification or deathblock.

Adamantine or any other armor with damage reduction would not be a good choice as it does not stack with the innate Barbarian damage reduction.

Shields
Barbarians are typically either 2-Handed or 2-Weapon fighters, and so rarely use a shield. DR Tanks would be the exception.

Because adamantine damage reduction does not stack with barbarian damage reduction, they would not be a good choice, but pretty much any other special effect on a shield could be used.

Weapons
One of everything.

Or, at least, one for every circumstance. Greater Bane weapons, Holy Cold-Iron weapons, etc.

For the most part, barbarians have little use for special effect weapons like banishers, vorpals, disrupters, etc. They typically deal enough damage that by the time the special effect lands, the mob could have been killed by straight damage.

Dwarf barbarians have more damage with great axes

Equipment
Stat Items - STR and CON are the two most important. DEX and WIS if you have room for them, just for the tiny bump to saving throws they would give.

Fortification Item - Heavy fortification is preferred, but even moderate fortification is better than nothing.

Featherfall Item - Standard item for all classes.

Underwater Action Item - Useful for all classes.

Jump Skill Item - Rarely needed on a barbarian since their strength lets them jump pretty well anyways, but sometimes a bit extra helps.

Balance Skill Item - Some DDO mobs love to trip, and you can't do anything while you're on your back. These aren't necessary all the time, but should be worn when facing mobs that trip.

Resistance Items - Especially anything that will boost reflex saves or will saves

False Life Item - Again, more hit points are always good.

Potions - Remove Blindness and Remove Disease just in case you get hit with something and the cleric can't get to you immediately. Lesser Restoration is something you should carry in bulk since it can not only get rid of several unwanted effects, but also gets rid of the fatigue after your rage ends (a clicky will work for the post-rage blahs, but pots are needed if you get hit by something while raging). And, you should also carry a large stack of healing potions since they are your only method of self healing.