Dungeon Keeper

PC

One of the biggest mysteries in Dungeon Keeper is what to sacrifice at the temple. Temples also make your monsters happier, can cure them of disease or chicken-ness. But the most fun is to drop your creatures into the temple waters too see what happens.

Here is what we've found so far:

Imps - Sacrifice a few of these little guys and they get much cheaper to create! Well worth it.
Fly & Spider - Get a Warlock
2 Beetles - Complete current manufacturing
2 Flies - Complete current research
Beetle & Spider - Get a Dark Mistress
Dark Mistress & Bile Demon & Troll - Get the Horned Reaper (sometimes)

Do NOT sacrifice the undead, or chickens, unless you like making the gods angry.

Speaking of the Horned Reaper, he's a great fighter, but can go a bit bezerk at times. If he gives you too much trouble, you can pay him off by dropping money on him. Makes him happier.