First off, I would like to thank all of you for responding with some really great advice. After much deliberation, I have finally arrived at the following party choice. The more time I spend thinking about this problem the more I realize that the Archer is by far the toughest character to fit into a well-balanced party, at least in my experience, since he cannot really function as a second tank and is restricted solely to missile support. This means one of the middle slots better served by perhaps a better thief or caster is lost.
By well-balanced I mean melee ability, clerical ability, spellcasting, thieving and the potential for romance. I also want to be able to use a wide variety of weapons with no overlap in proficiencies from character to character. Plus a good mix of alignments in order to have as much dialogue as possible - to me, this just serves to increase the roleplay factor.
The hardest part was deciding whether or not to take Keldorn. In the end I decided to leave him behind since I feel that once you retrieve Carsomyr he essentially becomes overpowered. My last full run through the game with a Jester I had him as my main tank and found by the end of the game that I wasn't really using the rest of the party. Basically Keldorn had become a one-man show, and battles that should have been tougher were simply a cakewalk.
So without further ado, and thanks in large part to some excellent advice, I've decided to go with the following party.
1) CG Minsc - main tank
2) TN Jaheira - second tank, romantic interest
3) NG Archer - missile attack, mage disruption
4) Viconia - main cleric
5) Nalia - main mage (would have taken Edwin but could never betray Minsc like that)
* after Spellhold, Imoen replaces Nalia
6) Jan - main thief, backup mage, great dialogue
* after Suldanessellar, Sarevok replaces Jan and become main tank
And there you have it. Hopefully this will be the group to keep me from falling off the wagon and ending up in Restarters Anonymous... again.
Cheers,
ElvenKing