Play what class-mixed party you like. It could be easy or hard, but never impossible and always fun.

You could use one monk, when you plan going the dark way. Monk's dark promotion has access to Disarm trap on master level and he is formidable melee fighter (after reaching GM Dodging, Unarmed and Staff).

I'd choose sorcerer, druid, paladin and monk.

The Warlock promotion quest is by far the hardest promotion quest in the game. I advise against having a Druid if you know you're going to choose the dark side, unless you like a serious challenge.

I generally do a single party (of a knight, an archer, a cleric, and a sorcerer) and save my game when the time comes to make the big choice. First I do one, then I go back to that save and do the other.

Since you've finished the game once already, you know which promotion quests on the neutral and good side are easier than which. Don't short-change yourself by including a class with a particularly tedious (to you) first promotion quest, again unless you like the challenge.

I like the Paladin, Archer, Cleric, Sorcerer combo best, since it gives you two who can cast high level healing magic and two who can cast high level mage spells. The Sorcerer gives you GM capability for ID Item and ID Monster, both very useful (and looks cool as a lich). The Cleric gives you GM level Merchant and the Archer gives you GM level Bow. The Paladin will give you GM Repair. My only regrets are not having GM in Alchemy for as many black potions as you can stand (which is fantastic for raising your stats through the roof), and no GM in Disarm Trap.

Hope that helps. Happy adventuring!

Well thanks everybody for the advice, i'm gonna play it again and follow the dark path.

P.S. Can't wait for MM8 liked that game too.