My most commonly used party setup is:

Keldorn
Minsc
Jaheira
Aerie
Protagonist(Sorcerer)
Imoen (temporarily Jan Jansen)

And I usually use the zigzag formation, like this:

.. Tank1(Minsc)
Healer1(Jaheira)
..Thief(Imoen)
Super Squishy Glas Cannon(Protagonist Sorcerer)
..Healer2(Aerie)
Tank2(Keldorn)

This way I'm well defended both from the front and the rear.

What I really like about this setup is that it very beautifully works with the items you get. Figther items go to Jaheira, Ranger items to to Minsc, Paladin items go to Keldorn.

And in ToB Keldorn gets the Twohanded sword +6, you know which one, Minsc gets the Halberd +6, Jaheira gets the Spear +6, and Aerie gets the Quarterstaff +6, thus distributing all +6 weapons you can get. Keldorn, Minsc and Jaheira also go for two weapon style, and Protagonist, Imoen and Aerie get Improved Haste. Especially Minsc (who usually gets CROM FAEYR and the Defender of Easthaven) is a killer machine this way.

Depending upon the situation, Jaheira might sometimes tank, pre-ToB. She can get pretty good AC with a shield, the only problem is getting a decent weapon for her (Club or Scimitar only). She cant dish out damage this way, but her high AC means she doesnt get much damage. Jaheiras other problem is the unbelievable "progression" of her Druid, who is just stuck for ages at level 14.

In ToB however all your tanks need is hitpoints, hitpoints, hitpoints, and as much damage reduction as possible. Armor class is worthless unless you would get somehow insane values. Opponents have riddiculous THAC0 like -10, they hit anything, all the time.

Minsc (and also by the way Valygar) get Armor of Faith, thats very helpful. So would any non-Inquisitor Paladin, of course. But then you lose the uber Dispel Magic.

And while you can get away with a lot in BG2 SoA, in ToB you really want two healers with Heal, one for each tank.

But Protection from Magical Weapons only lasts five rounds ?

When I played F/M I think I swapped Jaheira for Cernd instead.