I actually quite like the explosion, the little ball of light in the center is quite good.
It would be good for big ship explosions, like capships going down, but no for things like torpedoes.
And if you view an expanding sphere from the side, it looks like a circle getting bigger, so i think the circular explosions are alright.
If flat (or flattish) explosions were to be used, i think they would look quite good in place of spherical ones when a ship like the collosus explodes. Since it splits in 2, the shockwave could travel out along the axis it has exploded, so it would look like the shockwave cuts the sip in half.
pete
EDIT (a few hours later): I LOVE THIS EXPLOSION. Its much prettier than the normal one, and i like how its at an angle. If you get a ship which makes more than one shockwave when it dies its much more beleivable, since all the shokwaves go out at different angles.
I have a pic but dont have a site to host it from.
Try it yourself, set a sathanas or collosus to self destruct in FRED, and watch the fireworks!
One problem i did find though, was that when my sathanas exploded, the shokwave expanded much too slow, ie. 2 parts of the sathanas debris had seperated and blown up, and the shockwaves were still 6 little white balls in the middle.
Dunno whats to blame for that.