No cheating, no mods. You can either create a party with Bioware (only!) NPCs or create up to six party members of your own (or a combo of the two). No 3rd party NPCs please.

Six sorcerors.

bollocks, sorry illumina, but i think yu beed at least one fighter or somebody capable of mellee. i think ranger cleric, is the best bet. hey im back again, nice to be back. i would have at least 2 sorcerors, two ranger clerics or similar and 1 fighter, probably beserker, dwarf most likely and then 1 something else.

If I had to create such a party from scratch:

Monk - at higher levels these guys have incredible power. Quivering palm, ridiculous magic resistance, fast movement, stealth. I would put some proficiencies in axes as there are some very nice throwing axes in the game so he can have some ranged attacks…otherwise let his fists do the talking

Berserker  Mage -- Dual a Berserker at to a Mage at level 9 or 12. Incredibly powerful, more so than the fabled Kensai  Mage largely because of the lack of restriction regarding gauntles/bracers. Proficiencies in dual wielding katanas and long swords.

Sorcerer -- the ultimate spell caster. Proficiencies in quarterstaffs

Fighter dueled early (say level seven…sort of like Anomen) to Priest of Lathander. Proficiencies in flail and mace and hammers to make use of three of the games uber-weapons, the FoA and the improved Mace of Disruption and Crom Faeyr. Eventually he can dual wield FoA and Crom in his off hand

Bounty Hunter. Sneaky and able to set traps galore. Tansheron's Bow and either daggers or long swords

Inquisitor - This guy's major plus is his Dispel Magic ability, which he casts at twice his level, and he comes immune to Hold and Charm spells. His automatic high Charisma makes him the ideal front man for the group. Proficiencies in two handed swords and crossbows

Actually, Illumina's idea is very much viable. Of course... a Six Sorcerers game would be pretty boring... because it would be too damned easy.

I'd disagree with Illumina slightly. The ultimate powergaming party is one sorcerer.

How about three sorcerers?

how about 4?