Artificer equipment

Universal gear
Artificers, as all characters, benefit from the best fortification, constitution, and HP items available. Good Luck gear is an excellent use of a slot as well.

Spellcasting equipment

 * Artificers have several decent electric spells / SLAs. Consider using Magnetism / Lightning Lore items to increase their benefit.
 * Flame Turret is affected by Combustion / Fire Lore.
 * Blade Barrier is affected by Impulse / Kinetic Lore
 * Consider also Reconstruction or Devotion, if you're using them to heal.
 * Evocation focus items to improve DC of your electric spells, Blade Barrier, Tactical Detonation, and your Runearms.
 * Items that grant/regenerate SP
 * Ring of Spell Storing is particularly nice for capstoned arcanotechnicians who can use it for greater effect at CL20

Rogue equipment
To detect and disable traps, carry the best skill bonus items available. These don't have to be slotted permanently. Carry a lot of thieves' tools.

Armor
Many artificers have high dexterity and they can actually have a meaningful AC early in the game. At mid levels and later, AC becomes less important without significant focus, look instead for useful effects. Consider e.g. Snakeskin Vest or Parasitic Breastplate with uncanny awareness.

For warforged artificers, Blademark's Docent is a great choice early on; similar item can be also created via Cannith Crafting. At mid levels, life shield docent of greater/superior stability is an OK crafting choice.

Weapons
Most artificers use repeating crossbows. At mid levels, you will want to carry multiple crossbows. A paralyzer is party friendly. Great crossbows that trip on a natural 20 are also nice in groups.

Conjure Bolts increases enhancement level of ammunition up to +6 at level 20. This allows an artificer to effectively use a lower enhancement bonus crossbow with good procs on it and still get very good base damage as well. While Battle Engineer enhancements don't affect bolt enhancement levels, the combination of enhancements and Conjure Bolts give artificers more options with crossbows.

Other gear to consider:
 * Wind Howler Bracers increase your ranged attack and damage
 * Quiver of Poison adds a small amount of damage but occupies a slot generally unused by artificers.

Rune Arms
Rune arms are not created equal. Different rune-arms, even of the same elemental type may have different aiming, range, and down-range effect differences. Generally, force and acid rune arms are "lock on" and fire targeting with good long range accuracy unless the shots hit something on the way. Fire rune arms may be short range, "point and shoot" or longer ranged, fire-ball launching effects.

Other notes about rune arms:
 * Flame rune arms can be used to open "bashable" doors.
 * Cannith craftable rune arms can have a Shard of Masterful Craftsmanship applied to reduce the minimum level by 2. Additionally, Rune Arms are treated as trinkets by the Cannith Crafting system.
 * Fire-ball type rune arms (Animus, for example) can splash damage through magic barriers and doors.
 * The lowest level Tier 5 rune arm is Tira's Splendor at level 15. It does light damage, includes healing amplification and deathblock, and adds the silver damage flag to weapons.
 * Most rune arms are found as rewards at the end of quest chains. For free-to-play players (who have purchased the Artificer class), there may be some difficulty acquiring rune arms. Only a very limited number of them are not Bound to Account and those few—which are Bound to Character on Equip—often command premium prices on the Auction House.
 * Rune arms that have been crafted on may be returned to original state by putting them in a crafting device located in House Cannith or in Eveningstar.
 * "Simple", generic rune arms of various types are purchasable via the DDO Store.

Misc
Artificers can get a respectable UMD earlier than most other classes. Therefore, it is often useful to carry a wide variety of wands and scrolls; both to save SP as well as to expand their casting repertoire. Artificers also get improved benefit from clickies.