What character classes and multiclasses are the most useful and why in your opinion?

Which recruitable NPCs are the most useful and why?

I prefer wizards over sorcerers, but I don't mind being proved otherwise.

I dislike all the NPCs simply because they loot to some degree, and you cannot take these items from them. They will loot things they cannot use, don't always sell them when you go to a merchant, and they will even encumber themselves with things they cannot use. There are no interesting dialogues or interactions, some of the evil ones will turn on you, and some of the good aligned ones will leave your party.

I find it best to create a party that meets all the games needs and ignore the NPCs.

That said, I consider fighters to be the most useful party members - use rangers, paladins, and barbarians as your preferences dictate. Beware that paladins can fall rather easily in this game.
Rogues are almost useless, but there are a few dors and locks they can pick - but you can also use a mage with knock spells. I typically have my wizard take skill points in open lock (any character can do this and you'll be able to open any of the locked things you encounter).
A wizard or sorcerer is important for crafting magic items, and in ToEE I prefer the wizard simply because they get more feats.
Clerics will be helpful for healing, and they can also craft items, as well as being fairly decent combatants.
Bards and druids are fairly useless, as is usually the case in many games, but the druid is a little more functional in ToEE due to healing, more offensive spells, and a good animal companion option at higher levels (polar bear).
Monks are dicey in the beginning, but at 10th level are quite formidible.

I don't do any multiclassing with a 10th level cap, since I want my party to be good at their particular class rather than split.
I successfully play with 4 fighters and a wizard. I assign feats and skills to my fighters that model them slightly in the roles of paladin, ranger, and barbarian, but prefer the fighter class to the aforementioned becasue they get more feats and have fewer restrictions.

:cool:

All of the classes are "useful" in some way or another. What really matters is the overall party. The key is to know each character's strengths and take them into account when forming your party.

With a Level 10 limit in the game,(the biggest flaw of the game IMHO) don't bother with any multiclass characters.

The walkthrough made by JaggedJim that is available on this website has a great section in the beginning about good party combinations. Even if you would rather not read any of the walkthrough portion, download it for the strategy guide that precedes the actual walkthrough.

Personally, I like to avoid Paladins because they restrict your choices in the game too much. Use a good Cleric where you would want a Paladin. Fighters are nice because you get to customize them more with the extra feats they get. Barbarian Rage and extra hitpoints make Barbarians a strong addition to any party. I will always choose a Wizard over the Sorcerer because they can learn new spells from scrolls.

I will not go through every class in the game, deciding for yourself is what makes Role Playing games fun.

In response to the previous post: Rogues are more useful in combat than for opening locks. Any Wizard with a Knock spell can open a lock, but the Rogue is the only one who can backstab, (Attack of Opportunity or AoO) and the only one who gets Crippling Strike. In actual gameplay, a good Rogue will get an AoO almost every round, even on hard to hit monsters. Crippling Strike is only useful on larger monsters, but there are plenty of those in ToEE. Craft your Rogue Gloves of Dexterity +6 and get the Weapon Finesse feat, then watch him/her do 30+ with a Dagger.

Also, do not overlook the value of Craft Magic Arms and Armor and Craft Wondrous Item. I would give both of these feats to my Wizard and my Druid/Cleric. There are very few items in the game that are more powerful than the ones you will craft.