My group the first time through:
Me (CG Elven Archer)- Using mostly longbows, but in melee dual wielding Foesbane and Axe of the Unyielding (though he would switch to Azuredge against undead)
Minsc - He was using the Ravager, though he switched to Mace of Disruption against undead. Backed up Archer with the long bow.
Anomen - Dualwielding Crom Faeyr and Flail of Ages, he was actually my main tank (put gauntlets of dexterity, good armor, and the ring of gaxx on him, and he makes a solid tank). He used his spells for buffing and for precombat summons, as well as postcombat healing (we used the (many) healing potions during combat).
Aerie - Wielding Staff of the Magi (to keep her safe) and Robe of Vecna (to have both fast cleric and mage spells), she was quite nasty in my party. Would switch to sling of everard for missile support. She would occasionally lend out the staff to Imoen when I needed Imoen to sneak around. Aerie concentrated her cleric spells on extra summons for during combat, offensive spells like Holy Smite and Storm of Vengeance, and some summons. Mage spells concentrated on Breaching spells, with some summons and attack spells. In other words, a perfect support character.
Nalia - wearing the +5 chainmail that gives immunity to normal weapons (forget the name) and wielding the staff of the ram, she was actually quite lethal when the party got flanked. She stuck with Tasheron's Bow throughout the game. She had most of the mage buffing spells memorized, along with attack spells, major summons, and some breaching.
Imoen - wore robe of the good archmage, and wielding gesen bow and celestial fury (for backstabbing). In addition to thieving, she was the main mage, with well-rounded spell selection.
Actually, when I played the game, I relied mostly on fighting, using magic only when necessary. However, when we did use our magic, we REALLY put a hurting on opponents. There were only a few fights that were really tough, but they are the same ones everyone else says are tough. Otherwise, we annihilated Firkragg, the Shadow Dragon, even the Twisted Rune and Slavers (with some strategy, of course
). I actually used Yoshimo instead of Imoen until I got her back (hey, Good is hurting for thieves in this game).