I'm not sure if I've already posted in this thread (but apparently I voted already, and my opinion now is the same as then) but I like darkness comboed with entropy. There's the obvious Lycanthrope thing, there's antimatter/liquid shadow, you get steal, which is better than butterfly effect for permanent control, and you get a better shield in dusk, and a choice between two excellent weapons. Between the two elements, you have a lot of variation in creatures, from the super cheap lycanthrope to lifegaining vampires to gargoyle.
If I can ever get some darkness nymphs to go with my four (!) entropy nymphs, I'll -really- start having some fun...