A couple of suggestions: 1) Most of the fragmenting modifiers tend to give rather ordered results, but you can make things a bit more interesting and chaotic by applying two or more modifiers to the same object and some clever keyframing. 2) Stick a bulb in the middle of your exploding object and use the light sphere (on the bulb's effects tab). You can keyframe this to get a nice explosion effect, and also keyframe the light's colour so it falls off over time from white heat through yellow and orange to red. There are several other light effects on the same tab that you might find useful. Hope that helps!