Icewind Dale is an interesting game, with some good points and some bad points.
The good:
* Can create your entire party. (I prefer this style of RPG to the style where you get pre-made characters with their own personalities.)
* Game avoids some of the low level AD&D issues by having enough side quests in the starting town to take you to level 2 early. (This is very unlike Baldur's Gate 1.)
* Bard has some rather interesting songs.
* In the Classic Edition, you can create new characters mid-game, replacing older characters; unlike in IWD2, doing this doesn't make your other party members level up too fast, so no need to cheat just to keep the game balanced.
The bad:
* Real time with pause combat.
* Only way to move characters is to click on a spot and hope the pathfinding does its job; this becomes particularly obnoxious when there are traps and enemies in the same area.
* Some of the Enhanced Edition changes (including some of the "bug fixes") are rather questionable.
* Too much random treasure generation.
* Still has some AD&D issues, like blind weapon proficiency selection (you have to choose a weapon type to focus on, but you don't know what weapon types are well represented; the EE actually makes this problem worse by splitting proficiencies), and the fact that stats can't (easily) be improved once the game starts, meaning that you might start intending to dual-class, but then realize later that you can't and it's too late to fix that.
* Wizards (and Bards) don't learn spells at level up, and scrolls are scarce, so such characters can easily end up without critical spells, or even without any spells of the new spell level they just gained access to. (Worth noting that Clerics don't have this issue.)
The other:
* Combat feels better with the AI disabled. This is especially true if you have a bard in the party.
* Game balance and enemy composition heavily favors Clerics in this game. (Seems every classic AD&D title favors some class; in BG1, it's archers (fighters with bow proficiency); in BG2, wizards (and sorcerers); here it's clerics. (Dungeon Hack also favors clerics, albeit for slightly different reasons.)
Carradice: Some party might be this:
Paladin (Cavalier)
Fighter (dwarven)
Ranger (long range and eventuallly moving to the front line)
Thief (for locks, traps, ranged weapons, front line as a last resort)
Mage
Priest (or druid, going hand to hand if the party becomes overwhelmed)
But then, a bard might be helpful for identifying found objects on the go.
For IWD1, what I would tend to do:
* Definitely at least one Cleric. Maybe even more than one, because the game favors them so much (though an even better approach might be to take a smaller party so that your Cleric reaches a higher level, making Turn Undead more powerful). Many areas of this game are *filled* with undead. (There's a reason Rangers can't just choose "undead" as a favored enemy; the category is sub-divided because there are so many of them. Pathfinder: Wrath of the Righteous has a similar situation with demons.)
* There really isn't a Cavalier type here, at least not in classic IWD, and there's no mounted combat, anyway.
* Because scrolls are scarce, the Bard, if used, should replace the Mage, as there aren't enough scrolls for 2 arcane casters. Note that Bards eventually get access to level 8 spells (at level 29, IIRC), and in classic IWD there are only two level 9 spells, none of which are that great (and both are Conjuration, so some specialists may not have access to any spells of this level). Also, Bards have some neat songs in this game, and they level up faster than Mages, making the spells they do have available more powerful.