Max Squall (not Obscured Visibility, save that for later), then Static Charge. It will kill almost every normal monster for a good while.
Suggestion for build
Try Enslave Spirit and Vision of Death. They are decent 1 point skills, but not necessary. If you don't like them, buy the points back.
Dark Covenant is for mana regen, so you don't have have it, and it is more useful with more mana and int anyway, meaning you can try it in epic.
If you decide to go with Ternion, then put 1 pt in there, then max Arcane Lore, and Ternion after that.
Liche can be quite fragile in acts 3-4 normal, you can take him when you reach epic. Put enough pts in Wraith Shell so Liche doesn't die too often to your liking.