Abundance:

Stops you becoming hungry.

Eternal Youth:

Stops age showing while wearing the item. Meaning you still continue to age, but while wearing the item it will not show or effect you, but as soon as you remove the item, the age will go back up to what you would have been. So if you were 20 when you put the item on, then wear it for 50 years (game time), when you take it off you will be 70, which makes Eternal Youth quite useless.

Life Recovery:

Regenerates life points, much the same as the spell Berserker does.

Light Aura:

Generates a permenant aura of light around your character, similar to the time limited Light spell.

Mana Shield:

Mana points are taken away when hit instead of life (though when you're mana supply runs out, you begin losing life again until you replenish your mana supply). Invaluable for a mage.

Permenant Perception:

Traps show up in red. Some classes can learn this skill from Master Dalsin.

Poison's Effects Slowed Down:

Slows down the rate that you take damage from being poisoned.

Spell Duration Increased:

Doubles the duration of spells.

Quick Mana Recovery:

Mana regenerates in sets of 4 rather than 1 (e.g. 10, 14, 18, etc).

Faster Attack:

Increases your rate of attack.

Fastest Attack:

Increases your rate of attack even more.

Fire Element:

Imbues your weapon with a flame, which sets your opponent on fire, but doesn't do much damage. So while it looks good, it isn't of much use, and is more of a disadvantage because some creatures are immune to fire, and against those creatures you won't claim any other bonuses on the weapon. (e.g. with a sword that does 33-60 damage, +45 damage and Fire Element, against a creature immune to fire you will only get the 33-60.)

Magic Missiles:

Every time you hit something with your weapon, it casts Magic Missile without a mana cost, so the higher your Magic Missile spell level the better. Quite good to have, since the above disadvantage with Fire Element doesn't seem to apply with this one.

Poison:

This is suppose to poison your opponent, though personally I haven't seen it do much (never tried it against another player though). Also, there's the same disadvantage as with Fire Element.

Quick Recovery:

Allows you to recover faster after being hit.

Stone Curse:

Turns your opponent to stone when you hit them (unless they're immune to stone); the length of time depends on the level of your stone spell I think. It has the same disadvantage as Fire Element, but is a very useful enchantment none the less.

Storm:

Casts Storm without a mana cost when you strike something with your weapon, useful to keep enemies from surrounding you, though has that common disadvantage mentioned above.

Touch of Confusion:

Imbues your weapon with the Confusion spell, making your opponent a target in the eyes of other monsters, though he will still attack you. Has the same disadvantage as Fire Element.

Vampire:

Steals the life of you opponent, replenishing your own. This does not count any undead (e.g. skeleton, vampire) or bloodless (e.g. golems) creatures. So it's basically a permanent version of the Absorption spell, and is free of the disadvantage hindering some previously mentioned enchantments.

Curses will be hidden by a +all attribute property (e.g. +15 to all), then when you equip it, it will turn blue and reveal its true function (one of the curses listed below), and you will be unable to remove it by yourself. You will need to seek the help of Mistress Irma in town, and for a fee of 20000gp she will remove it for you. This is not to say all items with +all attributes will conceal a curse, but just be wary when you find one. Brought items are fine.

There are a couple of ways you can tell is an item is cursed, first of all cursed items generally have no requirements to meet (e.g. Plate Armour that would normally need 120 Strength, it would have no requirement listed instead). Another way is to try to sell it to Gunther the Blacksmith, he will sense that something is wrong, and offer you a much smaller price than what would normally befit an item with the +all attribute. Also, if it only has the +all and no other properties (such as if it has +15 to all and +40% to hit, this will not work), cast Detection and it will show up pink, instead of the usual blue.

Bulimia:

Increases your food consumption rate.

Leaking Pockets:

An item will drop out of your inventory every now and again.

Old Age:

Ages you by 50 years. So if you're 25, it will make you 75 years old, though you will return to 25 as soon as you have it removed.

Slow Motion:

Makes every movement extremely slow.

Unease:

This is mainly a multiplayer curse (though can be found in single player games). Your character will start shouting out challenges to other players, and making comments such as "There is a traitor amongst us". You are also able to remove this item without the aid of Mistress Irma.