Uh, Pyrenk, the Short Sword of Mask +5 is in ToB IIRC, not SoA. And I think the Dagger of the Star +5 is also in ToB, not SoA.
But my answer to that would be...Dragonslayer

. Works great on Minsc, finishing off his Red Dragon suit, giving him 100% fire resistance. Although he's not in my new party right now (kicked him out in the beginning of ToB for another character), but he kicked butt with it!