what is the best tam to have?

Welcome to the board.

The best team that someone can play is totaly dependend on your playing style. Some people don't like to play mages while others go with a magic heavy party. All are viable parties. This is my last party and i had lots of fun with it.
Paladin
Ranger
multi fighter/druid
cleric
thief
conjurer

Again this one is really down to choice and how you like to play the game but I always lean towards.
Fighter
Fighter
Paladin
Cleric
Thief / Mage
Mage / Cleric

I haven't play Icewind Dale very much but my party is:
Paladin
Fighter
Cleric
Thief
Conjurer
Fighter/Mage

Party choice is highly subjective and will depend a lot on the types of characters you like to play. For what its worth, I used this party to play through IWD / HOW in HOF mode:

Human Paladin
Half-Elven Ranger/Cleric
Half-Elven Fighter/Druid
Elven Fighter/Mage/Thief
Bard

This group gave me complete access to ALL spell groups and a good mix of all skills available in the game. The omission of a single class highly specialized fighter was not a huge loss in my estimation, but if you like the "mega-tank" concept, you can easily swap out the Paladin for a dwarven fighter. Playing in HOF mode meant that XP was NOT an issue for my multi-class characters, but if you play in standard mode, then you might want to consider playing single class characters to maximize spell lists. In that case, I would recommend this mix:

Paladin
Dwarven fighter
Cleric
Druid
Thief

Hope this helps.
Mage