Enchanter

An enchanter is a Mage specialized in the Enchantment school. His focus is Crowdcontrol and debuff.

Usefulness of different feats
The most important thing for a Enchanter is that his spells succeed. This makes Spell focus and Heighten Spell the most important feats.

Usefulness of different attributes
As with all spell casters the caster attribute is most important (int for Wizard and cha for Sorcerer). For an Enchanter this is even more true. Your spells tend to have an all or nothing effect so it is imperative that the monster fail its save against your spell. Otherwise the spell points used are essentially wasted. Personally I would reccommend putting a 17 in your casting ability score. DDO has action points that you can use to raise your primary casting ability later in the game by either one or three points. This way you free up four ability score points to offset hindrances elsewhere such as constitution and dexterity.