There are a wide variety of classes designed to suit many tastes:
Mage Subclasses:
Necromancer:
Master of the dark arts the Necromancer has a variety of skills dealing with death. Some of the more enjoyable are "Raise Dead" which brings to life the corpse of a creature just slain to do your bidding. Finger of Death is a powerful offensive spell. The Necromancer also possesses the ability to enchant weapons adding Flaming and Life draining abilities to the object.
Wizard:
The Wizard is more of a general all purpose mage with several fun skills. With a high Charisma the Wizard can use "Charm Person" to command an army of creatures. Wizards also posses some powerful attack spells with acid blast and chain lightning. Another favorite of the Wizard is enchanting weapons and armor.
Cleric Subclasses:
Priest:
Born to do the duty of his deity the Priest is well armed. He has the ability to summon elemental creatures of a wide variety to his beckon as well as call down the wrath of his god to blind, curse and further harass his enemies. A sturdy creature the priest can wear heavier armor than most of his spell casting brothers and sisters.
Druid:
The druids draw their power from the Earth. They have a knack for controlling the elemental creatures and can possess more than a priest can. Hapkido is a skill of the druids allowing them to hurt more with their staves. Combined with weapon empowering "Shillegrah", they can dish out a good deal of damage on their weapons alone.
Monk:
The monk classes posses a wide variety of skills to choose from so you may tailor your monk as you see fit. From access to a number of spell groups to the powerful 'Palm Strike' they posses some deadly skills. Masters of the art of hand to hand combat they can gain the ability to change their hands to other weapons and even add magical affects to them. The monk posses such a variety of offensive and defensive abilities.
Fighter Subclasses:
Warrior:
Masters of the art of Combat the warrior can wear the most powerful armors and wield the deadliest weapons in the land. The warrior has the ability to gain the most attacks per combat. The utilize Banzai as a tool to attack multiple enemies at one time.
Paladin:
The Paladin could be classed as a stronger cleric to an effect. The can wear all manner of weapons and armor and even bless their weapons with the faith of their Deity with the powers of 'Holy Forge' and 'Holy Avenger'. The can cast powerful spells which harm evil to a great effect.
Ranger:
Children of the woods they have gained the ability to move stealthily about. Having to relay on their own the have a wide variety of tools at their disposal. From more roguish abilities such as sneaking and lock picking, to minor spell casting the ranger meshes these with good fighting strength and the ability to summon forest creatures to aid in his defense.
Rogue Subclasses:
Assassin:
The name says it all. Designed to sneak in undetected and eliminate the opposition the Assassin has a few other tricks up his sleeve. If the powerful backstab does not kill the foe, they always have the knack of throwing things to cause damage. Should the need to flee arise they can drop Caltrops to the ground increasing their odds of escape.
Thief:
Whether it's picking pockets or picking locks the thief is always looking to turn a profit. They have several skills designed to help them relieve their target of their valuables. Of all else fails they can always backstab their way to profit.
Psioniscist:
The mysterious mind is the center of the Psions focus. They posses a range of skills from dominating creatures to the Psions will to a variety of skills designed to aid, the Psion's realm is toying with the will of the mind. Evil Psions' master the art of the Death Field, one of the most powerful spells in the game.
