Hellfire is definately a good spell but unless you're willing to spend money on a respec you should avoid putting 10 points into it. This is because the + skill items will not bring skills beyond level 10. Also as the previous poster explained, you will be very squishy running that build without venom armor and only level 1 arcane shield. I have to disagree on the tempest argument since Tempest is an amazing spell for all scenarios.