[Barlik Longbeard]

well the best choices for the character class would depend on what your allignment is. A straight mage and a straight cleric are the most powerful in the game because they can cast time stop and summon devas and pit fiends and stuff. The cleric can wear armour though which makes it much better than the mage. But the Cavalier and the Archer are the best scrips you could choose because they are killing machines and have very little disadvantages (excluding the armour restriction for the Archer, but rarely gets into close combat).
The best choice for the character class would be the cleric. This is because it can wear any armour, it can use the cromfayre or the flail of ages, it can use a shield, which would add quite a bit to your armour class, it can cast powerful spells and if it is hit it will continue to cast, unlike the mage, it can cast VERY powerful magics at a lower level than what a mage would cast it at and it can hold its own in close combat.
The cleric is by far the best, though I still haven't played as one yet. But I wouldn't say that a half-orc barbarian is crap: Constitution 19; Strength 19; bonus hp (added to the constitution 19 would have you with a final hp of about 350!); kicks rs in close combat; wears ne armour; can use the anti-mindflayer 2handed sword.