How about the following sequence:
Example: "Destroyer Death"
1. An All-Encompassing Flash, so bright that it blinds you 45 degrees from head-on. Could possibly add some kind of shadow effect on near-by ships, i.e. the silhouette of fighters against the hull of a cruiser or corvette.
2. 2-3 3d spherical, incandescent shockwaves slowly expand from the dying vessel, slowly fading as they expand out to a distance of about 800-1000 meters(the vaporized hull material). This looks vaguely like the supernovae in Star Trek: Generations.
3. Inside the shockwaves there is an amphorous blob of material, the remains of the mighty vessel's fusion plants, it twists and turns and looks like something alive struggling to escape a cocoon or an egg. It slowly stabilizes into a roughly spherical affair and fades from veiw as it consumes the remains of fuel inside the magnetic containment field. Note: This is visible primarily due to the brightness of the plasma. It should also flail about quickly enough so the veiwer can't quite nail the shape of it, but not so fast as to be all blurry.
4. All this should be accompanied by a powerful EM pulse that scrambles the electronics of all nearby ships. Player(s) would see this as the same effect as an EM missile or nebula storm, accompanied by some sort of movement on the part of nearby(1km) capital ships that suggests malfunctioning navigational systems and/or imbalanced drive systems with lightning crackling along the hull like they're heavily damaged.
Obviously, most of this is pie-in-the-sky talk but it gives an idea of what I envisioned.
