I am just using dynamic lights and the HDR shader. I have to admit, that it is really great, as long as you tweak it right. I also make heavy use of fog to illuminate the scene.
For the lava scene I wrote a special shader for the lava. It involves multitexturing, turbulence, an edge glow term & simple hotness estimation and fog supression (I am discounting the fog density, so that it "glows" still in heavy fog). For the foreground rocks I added a simply orange edge glow to simulate the red light emitted by the lava glow.
The aura is composed through sprites, so that it is resolution independent. And there are LOTS of particles in the scene(s) to make it feel vibrant and full of life.
The magma eruptions are particle effects, but with several different splatter images to get a "natural" eruption (see splatter category on cgtextures).
