Thats awesome! I have a very similar team that Im leveling now. The priest/warlock has some great synergy. I picked a DK as my tank. What modivated you to choose Pally as your tank?

I use Hellfire/Holy Nova most of the time. One guy watching me said Rain of Fire > Hellfire. The math says otherwise. Hellfire hurts but i just counterheal it with Holy Nova. With Realy Tough mobs I'll stagger out Shadowfury to stun them. This PB AoE is also useful for when a small number of enemy is meleeing you and its not practical to turn your army to face them.

I use the following DD if there are only 1 to 2 mobs in front of me. The spell casting times are selected to be near identical.

1.Vampric Touch/Immolate
2.Conflagrate/SW: Death
3.Mind Blast/Chaos Bolt
4.Mind Flay/Incinerate
5.Mind Flay/Incinerate

Rinse wash and repeat as desired. For Bosses and Hyper HP's mobs i begin with the two dots.