I choose the demonic foes, because there horde of them in the ToB and the watchers keep and there are many in the SoA part like planar sphere and the Kua Toa chambers.
The golems have too good physical resist so the +4 damage bonus is completely miss and a ranger has good thaco. And there are new antigolem spells in the game.
Rakashas also seems a good choice because you want beat some of them early and that time the +4 thaco and damage bonus is so good.
(Amióta folytattam a topicod kezdek angolul gondolkozni.
) Sorry, but i made a comment from my english in hungarian.