My Fire DPS Loadout: 1. Inferno 2. Fiery Weapon 3. Fireball 4. Fireburst 5. Mass Detonation 6. I use either an SC or Meteor (this would prolly annoy a lot of people but it helps to set enemies on fire.
A couple of people were asking me what my loadout was so here it is. Fire DPS can be frustrating if you don't do it well. Fire DPS is all about AoE and standing in the right spot. Fireburst and Mass Detonation can easily be interrupted so make sure you're in a safe spot when doing this. Make sure when you're doing Fireburst, be in range. Keep enemies on fire as this would increase you're critical chance. Fire is mainly focused on AoE damage so make sure when you do your skills, try to hit as many enemies as possible.
Directions for downloading and installing Mumble are in the General Section of the forums.