[Cerek the Barbaric]

I tried all sorts of "fancy" tactics on Kangaxx.
Yoshimo set as many traps as possible. I tried to PickPocket an "extra" Ring of Gaxx, etc.

Jaheira and Nalia would put up all sorts of protections and my fighters would use missile weapons....nothing worked.

Finally, I just quit being fancy and surrounded him with my fighters...
Cerek - Wizard Slayer 15th level.
Valygar
Keldorn
Yoshimo
Jaheira

They just did a straight "Pound Down" on him and killed him in under 3 rounds. He never even got to cast his infamous Time Stop.

I made sure that Cerek struck first, so that any spells would be directed at him. In addition to his Wizard Slayer Magic Resistance, he has a pair of gloves from Arundors Abode that reflect ANY spell below 6th level back at the caster (does NOT work with Area-of-Effect spells, though). That way, he focuses his attacks on Cerek and "most" of his spells either fizzle or zap him.